Index: trunk/src/org/openstreetmap/josm/io/session/SessionReader.java
===================================================================
--- trunk/src/org/openstreetmap/josm/io/session/SessionReader.java	(revision 17658)
+++ trunk/src/org/openstreetmap/josm/io/session/SessionReader.java	(revision 17659)
@@ -4,4 +4,5 @@
 import static org.openstreetmap.josm.tools.I18n.tr;
 
+import java.awt.Color;
 import java.awt.GraphicsEnvironment;
 import java.io.BufferedInputStream;
@@ -46,4 +47,5 @@
 import org.openstreetmap.josm.io.IllegalDataException;
 import org.openstreetmap.josm.tools.CheckParameterUtil;
+import org.openstreetmap.josm.tools.ColorHelper;
 import org.openstreetmap.josm.tools.JosmRuntimeException;
 import org.openstreetmap.josm.tools.Logging;
@@ -618,4 +620,13 @@
                 }
             }
+            String colorString = el.getAttribute("color");
+            if (colorString != null) {
+                try {
+                    Color color = ColorHelper.html2color(colorString);
+                    layer.setColor(color);
+                } catch (RuntimeException ex) {
+                    Logging.warn("Cannot parse color " + colorString);
+                }
+            }
             layer.setName(names.get(entry.getKey()));
             layers.add(layer);
Index: trunk/src/org/openstreetmap/josm/io/session/SessionWriter.java
===================================================================
--- trunk/src/org/openstreetmap/josm/io/session/SessionWriter.java	(revision 17658)
+++ trunk/src/org/openstreetmap/josm/io/session/SessionWriter.java	(revision 17659)
@@ -44,4 +44,5 @@
 import org.openstreetmap.josm.gui.layer.markerlayer.MarkerLayer;
 import org.openstreetmap.josm.gui.preferences.projection.ProjectionPreference;
+import org.openstreetmap.josm.tools.ColorHelper;
 import org.openstreetmap.josm.tools.JosmRuntimeException;
 import org.openstreetmap.josm.tools.Logging;
@@ -239,4 +240,7 @@
             if (!Utils.equalsEpsilon(layer.getOpacity(), 1.0)) {
                 el.setAttribute("opacity", Double.toString(layer.getOpacity()));
+            }
+            if (layer.getColor() != null) {
+                el.setAttribute("color", ColorHelper.color2html(layer.getColor()));
             }
             Set<Layer> deps = dependencies.get(layer);