Transparent Characters After Alt + Tab

[Blue306]

When I use PL/SQL Developer 16 and try to switch to another window using the Alt + Tab combination, the highlighted windows appear as shown in the attached image.

EDIT:
After closer inspection, pressing the Alt key is sufficient.

 

[Marco Kalter]

You can go to Preferences > User Interface > Key Configuration and disable the "Use default Alt shortcuts for Ribbon" option.

 

[Blue306]

Thanks, this will definitely help, but the program shouldn't bleed through to other windows.