Index: trunk/src/org/openstreetmap/josm/gui/ExtendedDialog.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/ExtendedDialog.java	(revision 5637)
+++ trunk/src/org/openstreetmap/josm/gui/ExtendedDialog.java	(revision 5638)
@@ -461,5 +461,5 @@
                 new WindowGeometry(rememberSizePref,
                         defaultWindowGeometry).applySafe(this);
-            } else {
+            } else if (isShowing()) { // should fix #6438, #6981, #8295
                 new WindowGeometry(this).remember(rememberSizePref);
             }