The items of a tree can be in 6 states. Your task is to design and implement visual appearence. An user should intuitively understand what happens immediately after looking at the tree.
=== States ===
A tree element can be "normal element" or "tag". The meaning of the tag is similar to one in web20, so the design should be similar to what is used in web20.
Both "normal element" and "tag" have three states:
1) "normal".
2) "deleted". I'd to strike-out or grey-out the item.
3) "contains deleted item". The item itself is not deleted, but somewhere inside the subtree there is something deleted.
=== Code ===
As the base, you can use attached "[login to view URL]". It fills wxTreeCtrl by items in the all six states, using six functions design_*.
Most likely, the task can't be done using wxTreeCtrl. Then you need to find an alternative under MPL, Python or similar free license (unfortunately, no GPL). The minimal supported wxPython version should be 2.8.11.