I just installed Visual C++ 6.0, Standard Edition. When I run an MFC app that I built with it, whenever I do an "Open", "New", or "Save As" operation, my program's window (which I have set to open maximized by default) resizes to take up about half the screen horizontally, and maybe two thirds vertically. The really strange thing is, the buttons in the title bar indicate that the window is still maximized (that is to say, the middle one is "Restore", not "Maximize".) If I restore and then maximize, the window takes up the whole screen again.
I had this problem when I installed VC++ 6 the first time, but within a week or two I installe Win98 and it went away. Now I had to uninstall it and reinstall it, and the problem is back. I'm still running Win98.