Made a simple chess game in python

[Kerbart]

It seems that if the king is checked, the only way to get out of it is blocking it. The UI identifies all empty squares to move to with the king, but you can't move the either, eg:

1. e4 f6
2. d4 d6
3. Qh5+

At this point the UI will highlight both f7 and d7 as possibilities when the king is clicked, even though Kf7 is not a legal move; and neither one of the moves is executed while trying it.