If there is only one part with that name in the tree view, the title should just be the part's name
Otherwise, add the document name, such as Document\Part
If that is still non-unique, perhaps the document path could also be added
Same principle for icon tabs, except that they have an extra parent (a part), e.g. Document.xlsm\customUI.xml\icon2.
Complementary thoughts:
It would be a good idea to show the full path in the status bar, e.g. C:\Path\to\document.xlsm\customUi.xml\icon2
Another option would be to select the item in the tree view as soon as the tab receives the focus, or doing this on demand through a context menu action
Follow-up of #58.
For editor tabs (i.e. for parts):
Document\PartSame principle for icon tabs, except that they have an extra parent (a part), e.g.
Document.xlsm\customUI.xml\icon2.Complementary thoughts:
C:\Path\to\document.xlsm\customUi.xml\icon2