I made the following observation with my Qt application itom (Qt5.15.2, Windows 10). In the following image you can see two screenshots.

• In the background, the application was started when a 4k monitor is defined as the main screen (scaling 125%). If I drag the plot window seen to the second monitor (fullHD, scaling 100%) I would expect that the widgets/icons should look slightly smaller.
• In the foreground, the application was started when the fullHD monitor is defined as the main screen (scaling 100%).

Now the question: Is the slight deviation in the size of the window content to be expected (e. g. axis labels)? Is there an explanation for this? I would expect that in both cases the window looks the same, since it is on the fullHD monitor with scaling 100%.

In the main function following settings are made in bothe cases:

SetProcessDpiAwarenessContext(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2); 
QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);

Thanks