I noticed a small bug at version 3.0.1 when I close an unsaved edited file.
Description:
1. I open a root document
2. I create a new file
3. I type something, the diskette symbol gets bold.
4. I close the file without saving
5. From now on, every time I use some visualization (F5, F7 or Ctrl + Click) a pop-up window appears asking me to save the closed file. Sometimes it asks to save the file as a dictionary.
6. When I close TeXstudio, it asks to save the closed file.