yeah it happen on my ubuntu 18.04. This issue happen with Tekken 7. Below the screenshot of the problem

Pro Evolution soccer has a configuration utility when you start the game (in Windows), where you can set the game in fullscreen. In linux, it's not shown at the start
Tekken 7 starts in borderless window mode.
How start Tekken 7 in borderless window mode? By default it start in fullscreen mode and demonstrate always black screen. So I can't enter in game settings for change fullscreen to borderless window.
Same for me, I can have the game fullscreen when changing the resolution.
Is this bug on KDE or other desktop environments ?
Nothing extracted yet.
Some games don't start in full screen mode. Trying to Force It by ALT+ENTER gives no result.
I have two examples:
Pro Evolution soccer 2018 starts only in Windowed mode.
Tekken 7 starts in borderless window mode.
Should be a great idea to Force fullscreen (ideally in a per-game setting) either incapsulating the corresponding wine setting or forcing It by steam client itself.