[PATCH 0/1] MR4258: comdlg32: Perform case-insensitive comparison of extension in file dialog.

[Owen Rudge (＠orudge)]

If the user, when saving using `IFileSaveDialog`, types a filename with an extension that differs from that specified in the filter definition, an extra extension is appended to the resulting filename (e.g. "test.TXT.txt"). This behaviour does not occur on Windows.