You have done a great job on High DPI support in the latest component pack build, but there are still a number of glitches, one of which is the HTML hint. Make it a reasonable size on a 4k screen and the next hint display can nearly cover the screen if the window has been moved to a different monitor. When the app stays on one monitor, however, the scaling seems correct.
I am aware that the standard VCL hints behave in the same way. But our applications use HTML hints because they are so much better than the standard ones! It seems that part of the problem may be that the canvas font passed to HTMLDrawEx is always initialized to the DPI of the main monitor, even after the move. But trying to tweak either this or the size of the HintFont can break the hint size on a system with only one monitor.
There's also the curious case of the RealCursorHeight function inside ActivateHint, which might have been intended to add some scale information but which is never called.
Almost all our hints are standardized at 11pt and include line-breaks in the HTML text, so do not need a maxwidth setting. This should make things easier for me to try to get it working, but it doesn't.
Is this something we may expect to be addressed in your next build?