If setWindowFlag(Qt::FramelessWindowHint).  

The UI shows wrong scale and position when dragging the window back and forth between displays with different scaling settings.

Reproduction can be performed based on the example ”Qt\Examples\Qt-x.x.x\widgets\layouts\basiclayouts“.

step1: Add this->setWindowFlag(Qt::FramelessWindowHint); to Dialog::Dialog();

step2: Add individual drag functions. (to be able to drag with Qt::FramelessWindowHint);

step3: Run and drag the widget repeatedly between 2 monitors with one 100% scale settings, the other not 100%.

Then the APP will display various strange distortions, as shown in the screenshot I took.

The modified project for test has been added as an attachment.