Menu in main window has incorrect possition and scaling after series of manipulation on Windows 10:
1. You need to have 2 monitors connected with windows scaling on both 100%

2. Change scaling of primary(first) screen to 125%

3. Run project from attachment(dockwidgets.zip) and drag application to secondary(second) screen with scaling 100%. Note I added code to disable HiDPI and turn on Windows scaling:

...
int main(int argc, char *argv[])
{
    SetProcessDPIAware();
    QApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
    QApplication app(argc, argv);
...

4. Undock any of dock widgets and move it to Primary screen with scaling of 125%

5. Click on any main menu item and observe incorrect menu position and scaling

See video steps to reproduce here: IssueWithScaling.mp4