Unable to delete tab after creation without first saving sketch

[per1234]

Using Arduino IDE 1.8.3 with Windows 7 64 bit

1. Click downward pointing triangle icon to open tab menu.
2. New Tab
3. Enter tab name
4. Click "OK"
5. Click downward pointing triangle icon to open tab menu.
6. Delete
7. Click "OK" - Delete fails Could not delete "foo.ino"
   

If I save the sketch after creating the new tab I am able to delete it.

Maybe related to #6265

[per1234]

This issue no longer occurs for me in Arduino 1.9.0 beta build 37.

I believe it was fixed by #6388