isExposed() returns true also if window minimized or completely covered

isExposed() returns 'true' in cases where the documentation says it should be 'false'. E.g. when you minimize or cover it completely it returns false on Linuxes.

Steps to reproduce:
1. run the attached example
2. minimize the app
3. check the debug output when app is minimized

Expected result:

• isExposed() should return 'false' when the app is minimized

Actual result:

• isExposed() returns 'true'

This bug is making the autotests in the CI to be flaky and is slowing down the integration, that's why it's marked as P0.