All tad windows closed after error in only one of them

1. Open file in tad
2. Open new tad window
3. In the new window, try opening file that is e.g. already opened in excel -> you get an error
4. After pressing "OK" on the error - all tad windows are closed

Expected behavior : Only the window with error is closed. 

Even better: Implement a "Retry" functionality, so I can close excel and retry opening in tad