yocto/touch: Button in a dialog stays in pressed state if another button is pressed at the same time

Run attached example on a device with multi-touch capable touchscreen.

Tap "open" button which should open a dialog, then hold the button in the dialog down and touch the "test" button on the main window. Release the button and it still stays in pressed state.

This was seen on embedded device Qt 5.15 with linuxfb, but it is probably a generic issue. However, I can also see something similar with 6.5.1 using just keyboard and mouse by holding down space to keep the button pressed and click the other button with mouse.