Bug 153993 [Viewers] Common Baseclass for Tree/TableEditorImpl
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeEditorImpl.java
private int doubleClickExpirationTime;
    private ColumnViewer viewer;
    TreeEditorImpl(ColumnViewer viewer) {
        this.viewer = viewer;
        initCellEditorListener();
    }
    /**
     * Returns this <code>TreeViewerImpl</code> viewer
     * 
     * @return the viewer
     */
    public StructuredViewer getViewer() {
        return viewer;
    }
    private void activateCellEditor() {
    	ViewerColumn part = viewer.getViewerColumn(columnNumber);
    	Object element = treeItem.getData();
    	
    	if( part != null && part.getEditingSupport() != null && part.getEditingSupport().canEdit(element) ) {
    		cellEditor = part.getEditingSupport().getCellEditor(element);
    		if( cellEditor != null ) {
    			cellEditor.addListener(cellEditorListener);
                Object value = part.getEditingSupport().getValue(element);
                cellEditor.setValue(value);
                
                
                
                final Control control = cellEditor.getControl();
                cellEditor.activate();
                if (control == null) {