Index: trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java	(revision 14281)
+++ trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java	(revision 14282)
@@ -264,6 +264,6 @@
     /**
      * Determines if commands can be undone.
-     * @return {14281 true} if at least a command can be undone
-     * @since xxx
+     * @return {@code true} if at least a command can be undone
+     * @since 14281
      */
     public boolean hasUndoCommands() {
Index: trunk/src/org/openstreetmap/josm/tools/KeyboardUtils.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/KeyboardUtils.java	(revision 14281)
+++ trunk/src/org/openstreetmap/josm/tools/KeyboardUtils.java	(revision 14282)
@@ -205,4 +205,5 @@
                 // https://en.wikipedia.org/wiki/German_keyboard_layout
                 result.add((char) KeyEvent.VK_DEAD_CIRCUMFLEX);
+                result.add('ˆ'); // U+02C6 : dead/modifier circumflex
                 break;
             case "cs": // Czech
@@ -240,4 +241,5 @@
                 // https://en.wikipedia.org/wiki/QWERTY#Estonian
                 result.add((char) KeyEvent.VK_DEAD_CARON); // https://en.wikipedia.org/wiki/Caron
+                result.add('ˇ'); // U+02C7 : dead key/modifier
                 break;
             case "is": // Icelandic
@@ -302,4 +304,5 @@
             // Works also for Dvorak, https://en.wikipedia.org/wiki/Dvorak_Simplified_Keyboard
             result.add('`'); // U+0060: On US QWERTY, this is not a dead key
+            result.add((char) KeyEvent.VK_DEAD_GRAVE);
             result.add('ˋ'); // U+02CB: On International QWERTY, this is a dead key
             return result;