Bug 45144 [PropertiesView] Properties View label provider does not clear the image
Properties View does not clear the image when the LabelProvider.getImage() retrns null. Attached exmaple: I have added onto the org.eclipse.ui.examples.propertysheet example to provide a ColorLabelProvider that returns null image for black and an image for all other colors. Select "richard" and note there are no image displayed. Now select an color besides black, and the color image appears as expected. Now select the color black and notice that the color image is still there.
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/properties/PropertySheetViewer.java
* @param event the SWT tree event
	 */
	private void handleTreeCollapse(TreeEvent event) {
		if (cellEditor != null) {
			applyEditorValue();
			deactivateCellEditor();
		}
	}
	/**
	 * The expand icon for a node in this viewer has been
	 * selected to expand the subtree. Create the children 
	 * 1 level deep.
	 * <p>
	 * Note that we use a "dummy" item (no user data) to show a "+"
	 * icon beside an item which has children before the item is expanded
	 * now that it is being expanded we have to create the real child
	 * items
	 * </p>
	 *
	 * @param event the SWT tree event
	 */
	private void handleTreeExpand(TreeEvent event) {
		createChildren(event.item);
	}
	/**
	 * Hides the categories.
	 */
	
	void hideCategories() {
		isShowingCategories = false;