Bug 33184

Description pasdemoi 2003-02-25 20:53:45 EST

The jface.action.Separator class inherits the default AbstractGroupMarker 
class's isEnabled() method, which is hardwired to return true.

This makes it impossible to use separators in submenus (or top-level menus in 
menubars) where you want disabled behavior, i.e., the submenu should be grayed 
out and not pop open when pressed.  The problem is, MenuManager.updateMenuItem 
looks to see if there are any enabled items within the menu, and if so, forces 
the menu to be enabled.  The presence of a Separator within that menu means 
there will *always* be an enabled item.

The simplest fix is to just override isEnabled() to return false instead of 
true.  An easier fix might be to just change the superclass method 
AbstractGroupMarker.isEnabled.  Clearly I can override it myself, which is why 
this bug is rated as "trivial".

There is no visible difference to the separator due to this change.

Special note:  this problem is exacerbated by peculiar SWT behavior (which 
might itself be a bug):  if you double-click on a disabled menu item in a menu 
bar, that menu item will receive an SWT.Shown event (even though the menu has 
not been shown).  This causes MenuManager.updateMenuItem to be called, which 
leads to the behavior listed in the paragraph at the top of this report.  Thus, 
you can disable a menu, but double-clicking on it causes updateMenuItem to be 
called, and then the Separator causes it to become enabled, and the status of 
your menu has changed, and it's now visible, with all other entries still 
disabled!  Wierd!

I hope this write-up is clear.