Bug 275910 [Widgets] PaintListener on Tree not invoked when item count is 0
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
}
			}
		}
	}
	/**
	 * Register the context menu for the receiver so that commands may be added
	 * to it.
	 */
	private void registerContextMenu() {
		MenuManager contextMenu = new MenuManager();
		contextMenu.setRemoveAllWhenShown(true);
		getSite().registerContextMenu(contextMenu, viewer);
		
		if (!getSite().getId().equals(MarkerSupportRegistry.MARKERS_ID)) {
			getSite().registerContextMenu(MarkerSupportRegistry.MARKERS_ID,
					contextMenu, viewer);
		}
		Control control = viewer.getControl();
		Menu menu = contextMenu.createContextMenu(control);
		control.setMenu(menu);
	}
	/**
	 * Remove the category from the list of expanded ones.
	 * 
	 * @param category
	 */
	void removeExpandedCategory(MarkerCategory category) {
		getCategoriesToExpand().remove(category.getName());
	}
	/*