I'm working on an application in C++ using Visual Studio 2019. It has a single dialog through which all interaction with the user happens. Ever since I created this dialog, several weeks ago, there's been a troublesome issue which isn't there all the time, so I've ignored it, but now I'm trying to make further cosmetic changes and this is becoming intolerable, so if anyone can tell me what I'm doing wrong I'll be extremely grateful.
When I view the dialog in the dialog editor, I can drag the sides or bottom right corner to make it the size I want, but when I then build the program and run it, the dialog appears clipped. You only see part of the dialog which lies within a smaller rectangle at the top left. I'm pretty sure this "clipping rectangle", whatever it is, is a fixed size.
Back in the dialog editor, if I toggle any one of several of the options in the Properties window, a white rectangle appears. I'm pretty sure this is the self-same "clipping rectangle" but what on earth is it, where's it coming from, and how do I get rid of it?