Bug 126839 [DataBinding] IObservable refactoring
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/viewers/TreeViewerUpdatableTreeExtended.java
if (customEditor!=null) {
					if (customEditor!=column.getCellEditor()) {
						throw new BindingException("Different Cell Editors on Column: "+columnIndex); 
					}
				} else {
					customEditor = column.getCellEditor();
				}				
			}			
		}
		
		if (customEditor==null) {
			
			return new TextCellEditor(treeViewerDescription.getTreeViewer().getTree()) ;
		}
		
		for (int i = 0; i < classTypes.length; i++) {
			Column column = treeViewerDescription.getColumn(classTypes[i], columnIndex);
			column.setCellEditor(customEditor);
		}
		return customEditor;
		
	}
	
	protected ICellModifier createCellModifier(final IDataBindingContext dataBindingContext) {
		return new ICellModifier() {
			private Column findColumn(Class instanceType, String property) {
				int index = Integer.parseInt(property);
				return treeViewerDescription.getColumn(instanceType, index);
			}
			public boolean canModify(Object element, String property) {