Yeah, it took me a minute to wrap my brain around the obvious simple logic of all that.
If I placed a control manually X/Y and then the DPI resolution changes (duh) of course the relative X/Y position will change, relatively speaking. So technically, it was more a matter of "positioning" with the different DPI settings than the controls actually not scaling in size correctly.
Everything was scaling in "size" correctly, but they were not positioning themselves correctly on the DPI change... for obvious reasons... because I'd hard coded the positions at another DPI setting.
One of those real facepalm moments.
I mean... left 450 from the window border is here at one dpi...
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...but obviously somewhere else leftwards at a denser DPI setting...
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It was still 450, but at a different place relative to the window it's inside of. (facepalm)
Thanks man. I hope you don't mind me calling on you when I get stuck on stuff like this. I'd hate to be a pest.