Stopped buttons responding to key-shortcuts when they're not actually visible.

modules/juce_gui_basics/buttons/juce_Button.cpp

@@ -572,7 +572,7 @@ void Button::clearShortcuts()
 
 bool Button::isShortcutPressed() const
 {
-    if (! isCurrentlyBlockedByAnotherModalComponent())
+    if (isShowing() && ! isCurrentlyBlockedByAnotherModalComponent())
         for (int i = shortcuts.size(); --i >= 0;)
             if (shortcuts.getReference(i).isCurrentlyDown())
                 return true;