Index: /trunk/src/org/openstreetmap/josm/tools/InputMapUtils.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/InputMapUtils.java	(revision 14690)
+++ /trunk/src/org/openstreetmap/josm/tools/InputMapUtils.java	(revision 14691)
@@ -129,5 +129,6 @@
         c.getActionMap().put("ctrl_enter", a);
         c.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(stroke, "ctrl_enter");
-        Optional.ofNullable(a.getValue(Action.SHORT_DESCRIPTION))
+        Optional.ofNullable(a)
+                .map(x -> x.getValue(Action.SHORT_DESCRIPTION))
                 .map(String::valueOf)
                 .ifPresent(text -> Shortcut.setTooltip(a, text, stroke));