Ask for saving before executing operations
ref #6806 Implement operation framework for feature tree editor
ref #6746 Fix potential NPE
ref #6746 Add "Create Feature Tree" menu item
ref #6746 Hide menu items when nothing is selected
ref #6746 Add/adapt handlers for feature tree editor
ref #6746 Add details view for feature tree and feature node
ref #6844 Enhance message dialog when loading new tree in dirty view
ref #6762 Add context menu to CharacterEditor
ref #6806 Add context menu to feature tree editor