Wine: Keyboard not working after changing focus

I am currently trying to start “Sacred: Gold Edition” using wine on Ubuntu 18.10 using Wine 3.0.3. I managed to get it running, but it requires me to use a virtual desktop.

This is not really a big deal, but when switching windows (changing focus via Alt+Tab) the focus of my keyboard does never switch back to the wine window. That means, when start the application from console, switch back to the console and back to the window, I will still be typing in the console, even when the wine window is focused.

How can I get this to work?