Opencascade with Qt5

Hello,

we are using Opencascade 7.0.0 in a Qt 5.8 project.

There we have the problem, that the gui does not update anymore after opening a tab in the application with an occ widget and then minimizing and maximizing the application. These same happens if you open a tab with an occ widget of an maximized application and then switch to windowed mode.

You can still use the buttons, but e.g. the hover style of buttons or periodic updates of labels in the gui does not get applied anymore. Thus it seems, that the application is frozen.

I also checked version 7.1, but there it is the same.

Can anyone give an idea what this can cause?

Many thanks in advance