On my PC with Windows 7 SP 1, the borders of all non-resizable windows (for example all dialog boxes or the calculator) look like the left of the two images below. The border is far too thin and overlaps itself (look closely at the circled areas). The right image shows how it should look like, based on a web search.
All windows that have a resizable border look correct. Further research showed that the problem appears on all windows that lack the
WS_BORDER window style. Adding that style manually on a window (with the SetWindowLongPtr function) makes the problem go away, although that window is then resizable, which is generally undesirable.
Has anyone ever seen this problem before or has any idea where to search for the problem?