Probably the last tip is the IDE status bar that could help you in situation, where you have opened more files with the same name. The status bar displays full file path of the selected file in the popup window that is displayed during switching between opened files in the editor through CTRL+TAB short cut.
I have also created four issues, the issue #178090 that explains the problem and is basically umbrella for three issues:
If you have any comment about this issues, please write the comment directly into the issue. It's much better if it looks like that the issue is a voice of our users, then it looks like an idea of a NetBeans developer:).