Index: src/org/openstreetmap/josm/actions/FullscreenToggleAction.java
===================================================================
--- src/org/openstreetmap/josm/actions/FullscreenToggleAction.java	(revision 3536)
+++ src/org/openstreetmap/josm/actions/FullscreenToggleAction.java	(working copy)
@@ -15,6 +15,7 @@
 
 import org.openstreetmap.josm.Main;
 import org.openstreetmap.josm.tools.PlatformHookUnixoid;
+import org.openstreetmap.josm.tools.PlatformHookWindows;
 import org.openstreetmap.josm.tools.Shortcut;
 
 public class FullscreenToggleAction extends JosmAction {
@@ -72,7 +73,16 @@
         Frame frame = (Frame)Main.parent;
         frame.dispose();
         frame.setUndecorated(selected);
-        gd.setFullScreenWindow(selected ? frame : null);
+        if (!(Main.platform instanceof PlatformHookWindows)) {
+            // we cannot use hw-exclusive fullscreen mode in MS-Win, as long
+            // as josm throws out modal dialogs as well :-), see here:
+            // http://forums.sun.com/thread.jspa?threadID=5351882
+            //
+            // the good thing is: fullscreen works without exclusive mode,
+            // since windows (or java?) draws the undecorated window full-
+            // screen by default (it's a simulated mode, but should be ok)
+            gd.setFullScreenWindow(selected ? frame : null);
+        }
         frame.setVisible(true);
     }