Index: /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSLayer.java
===================================================================
--- /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSLayer.java	(revision 21795)
+++ /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSLayer.java	(revision 21796)
@@ -38,4 +38,6 @@
 import org.openstreetmap.josm.io.CacheFiles;
 import org.openstreetmap.josm.tools.ImageProvider;
+import org.openstreetmap.josm.data.Preferences.PreferenceChangeEvent;
+import org.openstreetmap.josm.data.Preferences.PreferenceChangedListener;
 
 /**
@@ -43,435 +45,450 @@
  * fetched this way is tiled and managed to the disc to reduce server load.
  */
-public class WMSLayer extends Layer {
-	protected static final Icon icon =
-		new ImageIcon(Toolkit.getDefaultToolkit().createImage(WMSPlugin.class.getResource("/images/wms_small.png")));
-
-	public int messageNum = 5; //limit for messages per layer
-	protected MapView mv;
-	protected String resolution;
-	protected boolean stopAfterPaint = false;
-	protected int imageSize = 500;
-	protected int dax = 10;
-	protected int day = 10;
-	protected int minZoom = 3;
-	protected double dx = 0.0;
-	protected double dy = 0.0;
-	protected double pixelPerDegree;
-	protected GeorefImage[][] images = new GeorefImage[dax][day];
-	JCheckBoxMenuItem startstop = new JCheckBoxMenuItem(tr("Automatic downloading"), true);
-	protected JCheckBoxMenuItem alphaChannel = new JCheckBoxMenuItem(new ToggleAlphaAction());
-	protected String baseURL;
-	protected String cookies;
-	protected final int serializeFormatVersion = 5;
-
-	private ExecutorService executor = null;
-
-	/** set to true if this layer uses an invalid base url */
-	private boolean usesInvalidUrl = false;
-	/** set to true if the user confirmed to use an potentially invalid WMS base url */
-	private boolean isInvalidUrlConfirmed = false;
-
-	public WMSLayer() {
-		this(tr("Blank Layer"), null, null);
-		initializeImages();
-		mv = Main.map.mapView;
-	}
-
-	public WMSLayer(String name, String baseURL, String cookies) {
-		super(name);
-		alphaChannel.setSelected(Main.pref.getBoolean("wmsplugin.alpha_channel"));
-		setBackgroundLayer(true); /* set global background variable */
-		initializeImages();
-		this.baseURL = baseURL;
-		this.cookies = cookies;
-		WMSGrabber.getProjection(baseURL, true);
-		mv = Main.map.mapView;
-
-		// quick hack to predefine the PixelDensity to reuse the cache
-		int codeIndex = getName().indexOf("#PPD=");
-		if (codeIndex != -1) {
-			pixelPerDegree = Double.valueOf(getName().substring(codeIndex+5));
-		} else {
-			pixelPerDegree = getPPD();
-		}
-		resolution = mv.getDist100PixelText();
-
-		executor = Executors.newFixedThreadPool(3);
-		if (baseURL != null && !baseURL.startsWith("html:") && !WMSGrabber.isUrlWithPatterns(baseURL)) {
-			if (!(baseURL.endsWith("&") || baseURL.endsWith("?"))) {
-				if (!confirmMalformedUrl(baseURL)) {
-					System.out.println(tr("Warning: WMS layer deactivated because of malformed base url ''{0}''", baseURL));
-					usesInvalidUrl = true;
-					setName(getName() + tr("(deactivated)"));
-					return;
-				} else {
-					isInvalidUrlConfirmed = true;
-				}
-			}
-		}
-	}
-
-	public boolean hasAutoDownload(){
-		return startstop.isSelected();
-	}
-
-	public double getDx(){
-		return dx;
-	}
-
-	public double getDy(){
-		return dy;
-	}
-
-	@Override
-	public void destroy() {
-		try {
-			executor.shutdownNow();
-			// Might not be initialized, so catch NullPointer as well
-		} catch(Exception x) {
-			x.printStackTrace();
-		}
-	}
-
-	public double getPPD(){
-		ProjectionBounds bounds = mv.getProjectionBounds();
-		return mv.getWidth() / (bounds.max.east() - bounds.min.east());
-	}
-
-	public void initializeImages() {
-		images = new GeorefImage[dax][day];
-		for(int x = 0; x<dax; ++x) {
-			for(int y = 0; y<day; ++y) {
-				images[x][y]= new GeorefImage(false);
-			}
-		}
-	}
-
-	@Override public Icon getIcon() {
-		return icon;
-	}
-
-	@Override public String getToolTipText() {
-		if(startstop.isSelected())
-			return tr("WMS layer ({0}), automatically downloading in zoom {1}", getName(), resolution);
-		else
-			return tr("WMS layer ({0}), downloading in zoom {1}", getName(), resolution);
-	}
-
-	@Override public boolean isMergable(Layer other) {
-		return false;
-	}
-
-	@Override public void mergeFrom(Layer from) {
-	}
-
-	private ProjectionBounds XYtoBounds (int x, int y) {
-		return new ProjectionBounds(
-				new EastNorth(      x * imageSize / pixelPerDegree,       y * imageSize / pixelPerDegree),
-				new EastNorth((x + 1) * imageSize / pixelPerDegree, (y + 1) * imageSize / pixelPerDegree));
-	}
-
-	private int modulo (int a, int b) {
-		return a % b >= 0 ? a%b : a%b+b;
-	}
-
-	private boolean zoomIsTooBig() {
-		//don't download when it's too outzoomed
-		return pixelPerDegree / getPPD() > minZoom;
-	}
-
-	@Override public void paint(Graphics2D g, final MapView mv, Bounds bounds) {
-		if(baseURL == null) return;
-		if (usesInvalidUrl && !isInvalidUrlConfirmed) return;
-
-		if (zoomIsTooBig()) {
-			for(int x = 0; x<dax; ++x) {
-				for(int y = 0; y<day; ++y) {
-					images[modulo(x,dax)][modulo(y,day)].paint(g, mv, dx, dy);
-				}
-			}
-		} else {
-			downloadAndPaintVisible(g, mv);
-		}
-	}
-
-	public void displace(double dx, double dy) {
-		this.dx += dx;
-		this.dy += dy;
-	}
-
-	protected boolean confirmMalformedUrl(String url) {
-		if (isInvalidUrlConfirmed)
-			return true;
-		String msg  = tr("<html>The base URL<br>"
-				+ "''{0}''<br>"
-				+ "for this WMS layer does neither end with a ''&'' nor with a ''?''.<br>"
-				+ "This is likely to lead to invalid WMS request. You should check your<br>"
-				+ "preference settings.<br>"
-				+ "Do you want to fetch WMS tiles anyway?",
-				url);
-		String [] options = new String[] {
-				tr("Yes, fetch images"),
-				tr("No, abort")
-		};
-		int ret = JOptionPane.showOptionDialog(
-				Main.parent,
-				msg,
-				tr("Invalid URL?"),
-				JOptionPane.YES_NO_OPTION,
-				JOptionPane.WARNING_MESSAGE,
-				null,
-				options, options[1]
-		);
-		switch(ret) {
-		case JOptionPane.YES_OPTION: return true;
-		default: return false;
-		}
-	}
-
-	protected void downloadAndPaintVisible(Graphics g, final MapView mv){
-		if (usesInvalidUrl)
-			return;
-
-		ProjectionBounds bounds = mv.getProjectionBounds();
-		int bminx= (int)Math.floor (((bounds.min.east() - dx) * pixelPerDegree) / imageSize );
-		int bminy= (int)Math.floor (((bounds.min.north() - dy) * pixelPerDegree) / imageSize );
-		int bmaxx= (int)Math.ceil  (((bounds.max.east() - dx) * pixelPerDegree) / imageSize );
-		int bmaxy= (int)Math.ceil  (((bounds.max.north() - dy) * pixelPerDegree) / imageSize );
-
-		for(int x = bminx; x<bmaxx; ++x) {
-			for(int y = bminy; y<bmaxy; ++y){
-				GeorefImage img = images[modulo(x,dax)][modulo(y,day)];
-				if(!img.paint(g, mv, dx, dy) && !img.downloadingStarted){
-					img.downloadingStarted = true;
-					img.image = null;
-					img.flushedResizedCachedInstance();
-					Grabber gr = WMSPlugin.getGrabber(XYtoBounds(x,y), img, mv, this);
-					if(!gr.loadFromCache()){
-						gr.setPriority(1);
-						executor.submit(gr);
-					}
-				}
-			}
-		}
-	}
-
-	@Override public void visitBoundingBox(BoundingXYVisitor v) {
-		for(int x = 0; x<dax; ++x) {
-			for(int y = 0; y<day; ++y)
-				if(images[x][y].image!=null){
-					v.visit(images[x][y].min);
-					v.visit(images[x][y].max);
-				}
-		}
-	}
-
-	@Override public Object getInfoComponent() {
-		return getToolTipText();
-	}
-
-	@Override public Component[] getMenuEntries() {
-		return new Component[]{
-				new JMenuItem(LayerListDialog.getInstance().createActivateLayerAction(this)),
-				new JMenuItem(LayerListDialog.getInstance().createShowHideLayerAction(this)),
-				new JMenuItem(LayerListDialog.getInstance().createDeleteLayerAction(this)),
-				new JSeparator(),
-				new JMenuItem(new LoadWmsAction()),
-				new JMenuItem(new SaveWmsAction()),
-				new JMenuItem(new BookmarkWmsAction()),
-				new JSeparator(),
-				startstop,
-				alphaChannel,
-				new JMenuItem(new ChangeResolutionAction()),
-				new JMenuItem(new ReloadErrorTilesAction()),
-				new JMenuItem(new DownloadAction()),
-				new JSeparator(),
-				new JMenuItem(new LayerListPopup.InfoAction(this))
-		};
-	}
-
-	public GeorefImage findImage(EastNorth eastNorth) {
-		for(int x = 0; x<dax; ++x) {
-			for(int y = 0; y<day; ++y)
-				if(images[x][y].image!=null && images[x][y].min!=null && images[x][y].max!=null)
-					if(images[x][y].contains(eastNorth, dx, dy))
-						return images[x][y];
-		}
-		return null;
-	}
-
-	public class DownloadAction extends AbstractAction {
-		public DownloadAction() {
-			super(tr("Download visible tiles"));
-		}
-		public void actionPerformed(ActionEvent ev) {
-			if (zoomIsTooBig()) {
-				JOptionPane.showMessageDialog(
-						Main.parent,
-						tr("The requested area is too big. Please zoom in a little, or change resolution"),
-						tr("Error"),
-						JOptionPane.ERROR_MESSAGE
-				);
-			} else {
-				downloadAndPaintVisible(mv.getGraphics(), mv);
-			}
-		}
-	}
-
-	public class ChangeResolutionAction extends AbstractAction {
-		public ChangeResolutionAction() {
-			super(tr("Change resolution"));
-		}
-		public void actionPerformed(ActionEvent ev) {
-			initializeImages();
-			resolution = mv.getDist100PixelText();
-			pixelPerDegree = getPPD();
-			mv.repaint();
-		}
-	}
-
-	public class ReloadErrorTilesAction extends AbstractAction {
-		public ReloadErrorTilesAction() {
-			super(tr("Reload erroneous tiles"));
-		}
-		public void actionPerformed(ActionEvent ev) {
-			// Delete small files, because they're probably blank tiles.
-			// See https://josm.openstreetmap.de/ticket/2307
-			WMSPlugin.cache.customCleanUp(CacheFiles.CLEAN_SMALL_FILES, 4096);
-
-			for (int x = 0; x < dax; ++x) {
-				for (int y = 0; y < day; ++y) {
-					GeorefImage img = images[modulo(x,dax)][modulo(y,day)];
-					if(img.failed){
-						img.image = null;
-						img.flushedResizedCachedInstance();
-						img.downloadingStarted = false;
-						img.failed = false;
-						mv.repaint();
-					}
-				}
-			}
-		}
-	}
-
-	public class ToggleAlphaAction extends AbstractAction {
-		public ToggleAlphaAction() {
-			super(tr("Alpha channel"));
-		}
-		public void actionPerformed(ActionEvent ev) {
-			JCheckBoxMenuItem checkbox = (JCheckBoxMenuItem) ev.getSource();
-			boolean alphaChannel = checkbox.isSelected();
-			Main.pref.put("wmsplugin.alpha_channel", alphaChannel);
-
-			// clear all resized cached instances and repaint the layer
-			for (int x = 0; x < dax; ++x) {
-				for (int y = 0; y < day; ++y) {
-					GeorefImage img = images[modulo(x, dax)][modulo(y, day)];
-					img.flushedResizedCachedInstance();
-				}
-			}
-			mv.repaint();
-		}
-	}
-
-	public class SaveWmsAction extends AbstractAction {
-		public SaveWmsAction() {
-			super(tr("Save WMS layer to file"), ImageProvider.get("save"));
-		}
-		public void actionPerformed(ActionEvent ev) {
-			File f = SaveActionBase.createAndOpenSaveFileChooser(
-					tr("Save WMS layer"), ".wms");
-			try {
-				if (f != null) {
-					ObjectOutputStream oos = new ObjectOutputStream(
-							new FileOutputStream(f)
-					);
-					oos.writeInt(serializeFormatVersion);
-					oos.writeInt(dax);
-					oos.writeInt(day);
-					oos.writeInt(imageSize);
-					oos.writeDouble(pixelPerDegree);
-					oos.writeObject(getName());
-					oos.writeObject(baseURL);
-					oos.writeObject(images);
-					oos.close();
-				}
-			} catch (Exception ex) {
-				ex.printStackTrace(System.out);
-			}
-		}
-	}
-
-	public class LoadWmsAction extends AbstractAction {
-		public LoadWmsAction() {
-			super(tr("Load WMS layer from file"), ImageProvider.get("load"));
-		}
-		public void actionPerformed(ActionEvent ev) {
-			JFileChooser fc = DiskAccessAction.createAndOpenFileChooser(true,
-					false, tr("Load WMS layer"), "wms");
-			if(fc == null) return;
-			File f = fc.getSelectedFile();
-			if (f == null) return;
-			try
-			{
-				FileInputStream fis = new FileInputStream(f);
-				ObjectInputStream ois = new ObjectInputStream(fis);
-				int sfv = ois.readInt();
-				if (sfv != serializeFormatVersion) {
-					JOptionPane.showMessageDialog(Main.parent,
-							tr("Unsupported WMS file version; found {0}, expected {1}", sfv, serializeFormatVersion),
-							tr("File Format Error"),
-							JOptionPane.ERROR_MESSAGE);
-					return;
-				}
-				startstop.setSelected(false);
-				dax = ois.readInt();
-				day = ois.readInt();
-				imageSize = ois.readInt();
-				pixelPerDegree = ois.readDouble();
-				setName((String)ois.readObject());
-				baseURL = (String) ois.readObject();
-				images = (GeorefImage[][])ois.readObject();
-				ois.close();
-				fis.close();
-				mv.repaint();
-			}
-			catch (Exception ex) {
-				// FIXME be more specific
-				ex.printStackTrace(System.out);
-				JOptionPane.showMessageDialog(Main.parent,
-						tr("Error loading file"),
-						tr("Error"),
-						JOptionPane.ERROR_MESSAGE);
-				return;
-			}
-		}
-	}
-	/**
-	 * This action will add a WMS layer menu entry with the current WMS layer URL and name extended by the current resolution.
-	 * When using the menu entry again, the WMS cache will be used properly.
-	 */
-	public class BookmarkWmsAction extends AbstractAction {
-		public BookmarkWmsAction() {
-			super(tr("Set WMS Bookmark"));
-		}
-		public void actionPerformed(ActionEvent ev) {
-			int i = 0;
-			while (Main.pref.hasKey("wmsplugin.url."+i+".url")) {
-				i++;
-			}
-			String baseName;
-			// cut old parameter
-			int parameterIndex = getName().indexOf("#PPD=");
-			if (parameterIndex != -1) {
-				baseName = getName().substring(0,parameterIndex);
-			}
-			else {
-				baseName = getName();
-			}
-			Main.pref.put("wmsplugin.url."+ i +".url",baseURL );
-			Main.pref.put("wmsplugin.url."+String.valueOf(i)+".name", baseName + "#PPD=" + pixelPerDegree );
-			WMSPlugin.refreshMenu();
-		}
-	}
+public class WMSLayer extends Layer implements PreferenceChangedListener {
+    protected static final Icon icon =
+        new ImageIcon(Toolkit.getDefaultToolkit().createImage(WMSPlugin.class.getResource("/images/wms_small.png")));
+
+    public int messageNum = 5; //limit for messages per layer
+    protected MapView mv;
+    protected String resolution;
+    protected boolean stopAfterPaint = false;
+    protected int imageSize = 500;
+    protected int dax = 10;
+    protected int day = 10;
+    protected int minZoom = 3;
+    protected double dx = 0.0;
+    protected double dy = 0.0;
+    protected double pixelPerDegree;
+    protected GeorefImage[][] images = new GeorefImage[dax][day];
+    JCheckBoxMenuItem startstop = new JCheckBoxMenuItem(tr("Automatic downloading"), true);
+    protected JCheckBoxMenuItem alphaChannel = new JCheckBoxMenuItem(new ToggleAlphaAction());
+    protected String baseURL;
+    protected String cookies;
+    protected final int serializeFormatVersion = 5;
+
+    private ExecutorService executor = null;
+
+    /** set to true if this layer uses an invalid base url */
+    private boolean usesInvalidUrl = false;
+    /** set to true if the user confirmed to use an potentially invalid WMS base url */
+    private boolean isInvalidUrlConfirmed = false;
+
+    public WMSLayer() {
+        this(tr("Blank Layer"), null, null);
+        initializeImages();
+        mv = Main.map.mapView;
+    }
+
+    public WMSLayer(String name, String baseURL, String cookies) {
+        super(name);
+        alphaChannel.setSelected(Main.pref.getBoolean("wmsplugin.alpha_channel"));
+        setBackgroundLayer(true); /* set global background variable */
+        initializeImages();
+        this.baseURL = baseURL;
+        this.cookies = cookies;
+        WMSGrabber.getProjection(baseURL, true);
+        mv = Main.map.mapView;
+
+        // quick hack to predefine the PixelDensity to reuse the cache
+        int codeIndex = getName().indexOf("#PPD=");
+        if (codeIndex != -1) {
+            pixelPerDegree = Double.valueOf(getName().substring(codeIndex+5));
+        } else {
+            pixelPerDegree = getPPD();
+        }
+        resolution = mv.getDist100PixelText();
+
+        executor = Executors.newFixedThreadPool(
+            Main.pref.getInteger("wmsplugin.numThreads",
+            WMSPlugin.simultaneousConnections));
+        if (baseURL != null && !baseURL.startsWith("html:") && !WMSGrabber.isUrlWithPatterns(baseURL)) {
+            if (!(baseURL.endsWith("&") || baseURL.endsWith("?"))) {
+                if (!confirmMalformedUrl(baseURL)) {
+                    System.out.println(tr("Warning: WMS layer deactivated because of malformed base url ''{0}''", baseURL));
+                    usesInvalidUrl = true;
+                    setName(getName() + tr("(deactivated)"));
+                    return;
+                } else {
+                    isInvalidUrlConfirmed = true;
+                }
+            }
+        }
+
+        Main.pref.addPreferenceChangeListener(this);
+    }
+
+    public boolean hasAutoDownload(){
+        return startstop.isSelected();
+    }
+
+    public double getDx(){
+        return dx;
+    }
+
+    public double getDy(){
+        return dy;
+    }
+
+    @Override
+    public void destroy() {
+        try {
+            executor.shutdownNow();
+            // Might not be initialized, so catch NullPointer as well
+        } catch(Exception x) {
+            x.printStackTrace();
+        }
+    }
+
+    public double getPPD(){
+        ProjectionBounds bounds = mv.getProjectionBounds();
+        return mv.getWidth() / (bounds.max.east() - bounds.min.east());
+    }
+
+    public void initializeImages() {
+        images = new GeorefImage[dax][day];
+        for(int x = 0; x<dax; ++x) {
+            for(int y = 0; y<day; ++y) {
+                images[x][y]= new GeorefImage(false);
+            }
+        }
+    }
+
+    @Override public Icon getIcon() {
+        return icon;
+    }
+
+    @Override public String getToolTipText() {
+        if(startstop.isSelected())
+            return tr("WMS layer ({0}), automatically downloading in zoom {1}", getName(), resolution);
+        else
+            return tr("WMS layer ({0}), downloading in zoom {1}", getName(), resolution);
+    }
+
+    @Override public boolean isMergable(Layer other) {
+        return false;
+    }
+
+    @Override public void mergeFrom(Layer from) {
+    }
+
+    private ProjectionBounds XYtoBounds (int x, int y) {
+        return new ProjectionBounds(
+            new EastNorth(      x * imageSize / pixelPerDegree,       y * imageSize / pixelPerDegree),
+            new EastNorth((x + 1) * imageSize / pixelPerDegree, (y + 1) * imageSize / pixelPerDegree));
+    }
+
+    private int modulo (int a, int b) {
+        return a % b >= 0 ? a%b : a%b+b;
+    }
+
+    private boolean zoomIsTooBig() {
+        //don't download when it's too outzoomed
+        return pixelPerDegree / getPPD() > minZoom;
+    }
+
+    @Override public void paint(Graphics2D g, final MapView mv, Bounds bounds) {
+        if(baseURL == null) return;
+        if (usesInvalidUrl && !isInvalidUrlConfirmed) return;
+
+        if (zoomIsTooBig()) {
+            for(int x = 0; x<dax; ++x) {
+                for(int y = 0; y<day; ++y) {
+                    images[modulo(x,dax)][modulo(y,day)].paint(g, mv, dx, dy);
+                }
+            }
+        } else {
+            downloadAndPaintVisible(g, mv);
+        }
+    }
+
+    public void displace(double dx, double dy) {
+        this.dx += dx;
+        this.dy += dy;
+    }
+
+    protected boolean confirmMalformedUrl(String url) {
+        if (isInvalidUrlConfirmed)
+            return true;
+        String msg  = tr("<html>The base URL<br>"
+            + "''{0}''<br>"
+            + "for this WMS layer does neither end with a ''&'' nor with a ''?''.<br>"
+            + "This is likely to lead to invalid WMS request. You should check your<br>"
+            + "preference settings.<br>"
+            + "Do you want to fetch WMS tiles anyway?",
+            url);
+        String [] options = new String[] {
+            tr("Yes, fetch images"),
+            tr("No, abort")
+        };
+        int ret = JOptionPane.showOptionDialog(
+            Main.parent,
+            msg,
+            tr("Invalid URL?"),
+            JOptionPane.YES_NO_OPTION,
+            JOptionPane.WARNING_MESSAGE,
+            null,
+            options, options[1]
+        );
+        switch(ret) {
+        case JOptionPane.YES_OPTION: return true;
+        default: return false;
+        }
+    }
+
+    protected void downloadAndPaintVisible(Graphics g, final MapView mv){
+        if (usesInvalidUrl)
+            return;
+
+        ProjectionBounds bounds = mv.getProjectionBounds();
+        int bminx= (int)Math.floor (((bounds.min.east() - dx) * pixelPerDegree) / imageSize );
+        int bminy= (int)Math.floor (((bounds.min.north() - dy) * pixelPerDegree) / imageSize );
+        int bmaxx= (int)Math.ceil  (((bounds.max.east() - dx) * pixelPerDegree) / imageSize );
+        int bmaxy= (int)Math.ceil  (((bounds.max.north() - dy) * pixelPerDegree) / imageSize );
+
+        for(int x = bminx; x<bmaxx; ++x) {
+            for(int y = bminy; y<bmaxy; ++y){
+                GeorefImage img = images[modulo(x,dax)][modulo(y,day)];
+                if(!img.paint(g, mv, dx, dy) && !img.downloadingStarted){
+                    img.downloadingStarted = true;
+                    img.image = null;
+                    img.flushedResizedCachedInstance();
+                    Grabber gr = WMSPlugin.getGrabber(XYtoBounds(x,y), img, mv, this);
+                    if(!gr.loadFromCache()){
+                        gr.setPriority(1);
+                        executor.submit(gr);
+                    }
+                }
+            }
+        }
+    }
+
+    @Override public void visitBoundingBox(BoundingXYVisitor v) {
+        for(int x = 0; x<dax; ++x) {
+            for(int y = 0; y<day; ++y)
+                if(images[x][y].image!=null){
+                    v.visit(images[x][y].min);
+                    v.visit(images[x][y].max);
+                }
+        }
+    }
+
+    @Override public Object getInfoComponent() {
+        return getToolTipText();
+    }
+
+    @Override public Component[] getMenuEntries() {
+        return new Component[]{
+            new JMenuItem(LayerListDialog.getInstance().createActivateLayerAction(this)),
+            new JMenuItem(LayerListDialog.getInstance().createShowHideLayerAction(this)),
+            new JMenuItem(LayerListDialog.getInstance().createDeleteLayerAction(this)),
+            new JSeparator(),
+            new JMenuItem(new LoadWmsAction()),
+            new JMenuItem(new SaveWmsAction()),
+            new JMenuItem(new BookmarkWmsAction()),
+            new JSeparator(),
+            startstop,
+            alphaChannel,
+            new JMenuItem(new ChangeResolutionAction()),
+            new JMenuItem(new ReloadErrorTilesAction()),
+            new JMenuItem(new DownloadAction()),
+            new JSeparator(),
+            new JMenuItem(new LayerListPopup.InfoAction(this))
+        };
+    }
+
+    public GeorefImage findImage(EastNorth eastNorth) {
+        for(int x = 0; x<dax; ++x) {
+            for(int y = 0; y<day; ++y)
+                if(images[x][y].image!=null && images[x][y].min!=null && images[x][y].max!=null)
+                    if(images[x][y].contains(eastNorth, dx, dy))
+                        return images[x][y];
+        }
+        return null;
+    }
+
+    public class DownloadAction extends AbstractAction {
+        public DownloadAction() {
+            super(tr("Download visible tiles"));
+        }
+        public void actionPerformed(ActionEvent ev) {
+            if (zoomIsTooBig()) {
+                JOptionPane.showMessageDialog(
+                    Main.parent,
+                    tr("The requested area is too big. Please zoom in a little, or change resolution"),
+                    tr("Error"),
+                    JOptionPane.ERROR_MESSAGE
+                );
+            } else {
+                downloadAndPaintVisible(mv.getGraphics(), mv);
+            }
+        }
+    }
+
+    public class ChangeResolutionAction extends AbstractAction {
+        public ChangeResolutionAction() {
+            super(tr("Change resolution"));
+        }
+        public void actionPerformed(ActionEvent ev) {
+            initializeImages();
+            resolution = mv.getDist100PixelText();
+            pixelPerDegree = getPPD();
+            mv.repaint();
+        }
+    }
+
+    public class ReloadErrorTilesAction extends AbstractAction {
+        public ReloadErrorTilesAction() {
+            super(tr("Reload erroneous tiles"));
+        }
+        public void actionPerformed(ActionEvent ev) {
+            // Delete small files, because they're probably blank tiles.
+            // See https://josm.openstreetmap.de/ticket/2307
+            WMSPlugin.cache.customCleanUp(CacheFiles.CLEAN_SMALL_FILES, 4096);
+
+            for (int x = 0; x < dax; ++x) {
+                for (int y = 0; y < day; ++y) {
+                    GeorefImage img = images[modulo(x,dax)][modulo(y,day)];
+                    if(img.failed){
+                        img.image = null;
+                        img.flushedResizedCachedInstance();
+                        img.downloadingStarted = false;
+                        img.failed = false;
+                        mv.repaint();
+                    }
+                }
+            }
+        }
+    }
+
+    public class ToggleAlphaAction extends AbstractAction {
+        public ToggleAlphaAction() {
+            super(tr("Alpha channel"));
+        }
+        public void actionPerformed(ActionEvent ev) {
+            JCheckBoxMenuItem checkbox = (JCheckBoxMenuItem) ev.getSource();
+            boolean alphaChannel = checkbox.isSelected();
+            Main.pref.put("wmsplugin.alpha_channel", alphaChannel);
+
+            // clear all resized cached instances and repaint the layer
+            for (int x = 0; x < dax; ++x) {
+                for (int y = 0; y < day; ++y) {
+                    GeorefImage img = images[modulo(x, dax)][modulo(y, day)];
+                    img.flushedResizedCachedInstance();
+                }
+            }
+            mv.repaint();
+        }
+    }
+
+    public class SaveWmsAction extends AbstractAction {
+        public SaveWmsAction() {
+            super(tr("Save WMS layer to file"), ImageProvider.get("save"));
+        }
+        public void actionPerformed(ActionEvent ev) {
+            File f = SaveActionBase.createAndOpenSaveFileChooser(
+                tr("Save WMS layer"), ".wms");
+            try {
+                if (f != null) {
+                    ObjectOutputStream oos = new ObjectOutputStream(
+                        new FileOutputStream(f)
+                    );
+                    oos.writeInt(serializeFormatVersion);
+                    oos.writeInt(dax);
+                    oos.writeInt(day);
+                    oos.writeInt(imageSize);
+                    oos.writeDouble(pixelPerDegree);
+                    oos.writeObject(getName());
+                    oos.writeObject(baseURL);
+                    oos.writeObject(images);
+                    oos.close();
+                }
+            } catch (Exception ex) {
+                ex.printStackTrace(System.out);
+            }
+        }
+    }
+
+    public class LoadWmsAction extends AbstractAction {
+        public LoadWmsAction() {
+            super(tr("Load WMS layer from file"), ImageProvider.get("load"));
+        }
+        public void actionPerformed(ActionEvent ev) {
+            JFileChooser fc = DiskAccessAction.createAndOpenFileChooser(true,
+                false, tr("Load WMS layer"), "wms");
+            if(fc == null) return;
+            File f = fc.getSelectedFile();
+            if (f == null) return;
+            try
+            {
+                FileInputStream fis = new FileInputStream(f);
+                ObjectInputStream ois = new ObjectInputStream(fis);
+                int sfv = ois.readInt();
+                if (sfv != serializeFormatVersion) {
+                    JOptionPane.showMessageDialog(Main.parent,
+                        tr("Unsupported WMS file version; found {0}, expected {1}", sfv, serializeFormatVersion),
+                        tr("File Format Error"),
+                        JOptionPane.ERROR_MESSAGE);
+                    return;
+                }
+                startstop.setSelected(false);
+                dax = ois.readInt();
+                day = ois.readInt();
+                imageSize = ois.readInt();
+                pixelPerDegree = ois.readDouble();
+                setName((String)ois.readObject());
+                baseURL = (String) ois.readObject();
+                images = (GeorefImage[][])ois.readObject();
+                ois.close();
+                fis.close();
+                mv.repaint();
+            }
+            catch (Exception ex) {
+                // FIXME be more specific
+                ex.printStackTrace(System.out);
+                JOptionPane.showMessageDialog(Main.parent,
+                        tr("Error loading file"),
+                        tr("Error"),
+                        JOptionPane.ERROR_MESSAGE);
+                return;
+            }
+        }
+    }
+    /**
+     * This action will add a WMS layer menu entry with the current WMS layer
+     * URL and name extended by the current resolution.
+     * When using the menu entry again, the WMS cache will be used properly.
+     */
+    public class BookmarkWmsAction extends AbstractAction {
+        public BookmarkWmsAction() {
+            super(tr("Set WMS Bookmark"));
+        }
+        public void actionPerformed(ActionEvent ev) {
+            int i = 0;
+            while (Main.pref.hasKey("wmsplugin.url."+i+".url")) {
+                i++;
+            }
+            String baseName;
+            // cut old parameter
+            int parameterIndex = getName().indexOf("#PPD=");
+            if (parameterIndex != -1) {
+                baseName = getName().substring(0,parameterIndex);
+            }
+            else {
+                baseName = getName();
+            }
+            Main.pref.put("wmsplugin.url."+ i +".url",baseURL );
+            Main.pref.put("wmsplugin.url."+String.valueOf(i)+".name",
+                baseName + "#PPD=" + pixelPerDegree );
+            WMSPlugin.refreshMenu();
+        }
+    }
+
+    public void preferenceChanged(PreferenceChangeEvent event) {
+        if (event.getKey().equals("wmsplugin.simultaneousConnections")) {
+            executor.shutdownNow();
+            executor = Executors.newFixedThreadPool(
+                Main.pref.getInteger("wmsplugin.numThreads",
+                WMSPlugin.simultaneousConnections));
+        }
+    }
 }
Index: /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSPlugin.java
===================================================================
--- /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSPlugin.java	(revision 21795)
+++ /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSPlugin.java	(revision 21796)
@@ -53,4 +53,5 @@
     static int overlapEast = 14;
     static int overlapNorth = 4;
+    static int simultaneousConnections = 3;
 
     // remember state of menu item to restore on changed preferences
@@ -110,4 +111,9 @@
             overlapNorth = Integer.valueOf(prefs.get("wmsplugin.url.overlapNorth"));
         } catch (Exception e) {} // If sth fails, we drop to default settings.
+               
+        // Load the settings for number of simultaneous connections
+        try {
+            simultaneousConnections = Integer.valueOf(prefs.get("wmsplugin.simultanousConnections"));
+        } catch (Exception e) {} // If sth fails, we drop to default settings.
 
         // And then the names+urls of WMS servers
Index: /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSPreferenceEditor.java
===================================================================
--- /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSPreferenceEditor.java	(revision 21795)
+++ /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSPreferenceEditor.java	(revision 21796)
@@ -39,4 +39,5 @@
     JSpinner spinEast;
     JSpinner spinNorth;
+    JSpinner spinSimConn;
 
     public void addGui(final PreferenceTabbedPane gui) {
@@ -163,5 +164,4 @@
         p.add(browser);
 
-
         //Overlap
         p.add(Box.createHorizontalGlue(), GBC.eol().fill(GridBagConstraints.HORIZONTAL));
@@ -181,4 +181,13 @@
 
         p.add(overlapPanel);
+               
+        // Simultaneous connections
+        p.add(Box.createHorizontalGlue(), GBC.eol().fill(GridBagConstraints.HORIZONTAL));
+        JLabel labelSimConn = new JLabel(tr("Simultaneous connections"));
+        spinSimConn = new JSpinner(new SpinnerNumberModel(WMSPlugin.simultaneousConnections, 1, 30, 1));
+        JPanel overlapPanelSimConn = new JPanel(new FlowLayout());
+        overlapPanelSimConn.add(labelSimConn);
+        overlapPanelSimConn.add(spinSimConn);
+        p.add(overlapPanelSimConn);
     }
 
@@ -223,4 +232,5 @@
         WMSPlugin.overlapEast = (Integer) spinEast.getModel().getValue();
         WMSPlugin.overlapNorth = (Integer) spinNorth.getModel().getValue();
+        WMSPlugin.simultaneousConnections = (Integer) spinSimConn.getModel().getValue();
 
         Main.pref.put("wmsplugin.url.overlap",    String.valueOf(WMSPlugin.doOverlap));
@@ -228,5 +238,5 @@
         Main.pref.put("wmsplugin.url.overlapNorth", String.valueOf(WMSPlugin.overlapNorth));
 
-        Main.pref.put("wmsplugin.browser", browser.getEditor().getItem().toString());
+        Main.pref.put("wmsplugin.simultaneousConnections", String.valueOf(WMSPlugin.simultaneousConnections));
         return false;
     }