Well, that's odd. I could of course post a screenshot but it would only show the mouse pointer correctly centered horizontally over the default button, but appearing (consistently) vertically 32 pixels
above where it's supposed to be - so there's not much to see.
As I said, this happens for
all skins when "Skin Windows Borders" is selected, except the "Windows Theme" which disables that item anyway. If I manually untick the menu item, everything works fine.
I did try to search for similar complaints, but nothing turned up. It's not a new problem - I had it on an old Win7 machine, but considering I just re-installed (from scratch) Win10 a couple of weeks ago, it's not a system problem. I just assumed that most people untick the windows "Mouse Properties -> Pointer Options -> Auto-move pointer to default button in a dialog box" option for some reason.
I have no software running which effects the mouse (default drivers), nor anything which manipulates windows rendering itself (such as Window Blinds, etc.) I use a single monitor, with DPI at %125. I originally thought this could somehow be a DPI issue, but it's not - same behaviour at %100.
Just for laughs I just tried nuking my MB settings file (and .bak) but it makes no difference.
Moving the main-menu and/or the command-buttons toolbar in and out of the caption bar makes no difference. It can't possibly be a coincidence that the vertical offset is exactly the height of the caption bar.
This is absolutely consistent: for example, clicking Tools -> Convert Format the window opens and the pointer moves to above (but not ON) the Proceed button. If, however, I click on Tools -> Tagging -> Search and Replace the pointer moves to where it's supposed to be, perfectly centered on the Close button.
All that being said, if no one else can reproduce this issue, then I guess it's somehow a local problem, but I don't understand how it could only effect a single programme (MusicBee), and no others, and only when the borders are skinned.
I guess I'll just live with it - it's not exactly a huge problem, but it is a strange one.