Dropdown menu displaced on screen with mixed DPI

Dopus 12.6 on Windows 10 x64. I have two 80cm monitors with different native resolutions (2560x1600 and 3840x2160), so in Windows display settings I have scaling for the lower res monitor set to 100% and for the high res monitor set to 150% - this give screen elements that are approximately the same size on both monitors, and means that windows resize to about the same size when dragged between monitors.

I have found that if I start DOpus on the low res monitor and then drag its window to the high res monitor, when I click the button next to a drive or folder name in the current path shown at the top of a lister, the menu of choices that appears is displaced sideways and upwards (see attached screenshot, where I had clicked the button just to the left of D:). The problem doesn't happen with the menu items on the menu bar, nor does it happen if the DOpus window is initially opened on the high res monitor, nor if it is opened on the high res monitor and then dragged to the low res monitor.

You can also see on the screenshot that the font size of the choices that have appeared is smaller than it should be.

This is a bug in Windows 10 which can be triggered by pop-up windows (e.g. menus) when using monitors with a mixture of DPIs.

We've looked into it before and not found a way to solve it. The underlying problem is that we ask for the menu to be created on one screen (the screen it is on), but Windows sometimes then applies the DPI scaling of the other monitor to it. So the position and actual size/scaling of the menu is incorrect.

From what I could tell, Windows seems to get confused if some of Opus's windows, and possibly the currently active one, are on one monitor and you then trigger a menu to open on the other monitor.

Windows itself also has a lot of similar bugs when using a mixture of DPIs. I recommend avoiding it, and just using the DPI for one monitor or the other, as mixed DPI is still not bug-free in Windows. (For an obvious one, dock a toolbar to the bottom of one monitor, with the taskbar on another monitor, and see what the taskbar then does. Window borders are also not drawn correctly in this mode, if you look closely at the edges of them.)