Bug 4369 F2 should work even if "Hide Text Hover" is enabled
- enable "Hide Text Hover" - position the cursor on a type - press F2 observe: nothing happens although I explicitly requested JavaDoc help.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/hover/JavaTextHover.java
class EditorWatcher implements IPartListener {
		
		/**
		 * @see IPartListener#partOpened(IWorkbenchPart)
		 */
		public void partOpened(IWorkbenchPart part) {
		}
		
		/**
		 * @see IPartListener#partDeactivated(IWorkbenchPart)
		 */
		public void partDeactivated(IWorkbenchPart part) {
		}
		
		/**
		 * @see IPartListener#partClosed(IWorkbenchPart)
		 */
		public void partClosed(IWorkbenchPart part) {
			if (part == fEditor) {
				fEditor.getSite().getWorkbenchWindow().getPartService().removePartListener(fPartListener);
				fPartListener= null;
				
				IPreferenceStore store= JavaPlugin.getDefault().getPreferenceStore();
				store.removePropertyChangeListener(fPropertyChangeListener);
				fPropertyChangeListener= null;
			}
		}
		
		/**