Bug 56818 [PropertiesView] Clicking on Advanced Properties toggle when categories are collapsed removes the + next to the category
Clicking on Advanced Properties toggle when categories are collapsed removes the plus sign (+) next to the category and it can no longer be expanded. To reproduce: 1.)Open the Properties view. 2.)Have Show Categories turned on, and Show Advanced Properties turned off. 3.)Collapse all open categories. 4.)Click the Show Advanced Properties button. 5.)Note the plus sign goes away and the categories can no longer be expanded. You need to click the Show Advanced Properties button off to see the plus sign again.
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/properties/PropertySheetViewer.java
setErrorMessage(cellEditor.getErrorMessage());
		
		cellEditor.setFocus();
		
		fireCellEditorActivated(cellEditor);
	}
	/**
	 * Adds a cell editor activation listener. Has no effect if an identical
	 * activation listener is already registered.
	 * 
	 * @param listener
	 *            a cell editor activation listener
	 */
	
	void addActivationListener(ICellEditorActivationListener listener) {
		activationListeners.add(listener);
	}
	/**
	 * Add columns to the table tree and set up the layout manager accordingly.
	 */
	private void addColumns() {
		Table table = tableTree.getTable();
		
		TableColumn[] columns = table.getColumns();
		for (int i = 0; i < columnLabels.length; i++) {
			String string = columnLabels[i];
			if (string != null) {
				TableColumn column;
				if (i < columns.length)
					column = columns[i];