This fix is needed for the Delphi GUI programs.
- Don't enumerate the windows whose owner window exists.
- Use PostMessage SC_RESTORE instead of ShowWindowAsync SW_RESTORE.
CORE-15165
When we unselect text after the WM_CBLOSTTEXTFOCUS message,
make sure we also forget we have been focused at all;
otherwise the edit may become focused again, but with an
empty text selection.
CORE-10266