Index: trunk/src/org/openstreetmap/josm/gui/dialogs/PropertiesDialog.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/PropertiesDialog.java	(revision 2382)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/PropertiesDialog.java	(revision 2383)
@@ -130,4 +130,11 @@
             }
         }
+        @Override public void mousePressed(MouseEvent e) {
+            if (e.getSource() == propertyTable) {
+                membershipTable.clearSelection();
+            } else if (e.getSource() == membershipTable) {
+                propertyTable.clearSelection();
+            }
+        }
     }