Virtual Keyboard Stays On Screen After Return Key Pressed And Crash Happens

Virtual Keyboard is working on a linux application.

When i try this on my local machine I can't reproduce it. But with VNC i could manage to crash the application.

This error happened after we migrated our qt from 5.12.11 to 5.15.10.

Steps:

1. Open Virtual Keyboard by clicking a lineedit.
2. Close the Page by Clicking A button.
3. Virtual Keyboard is not destroyed.