On Microsoft Windows Vista, Windows 7, Windows 8 and Windows 10 LispWorks is themed . That is, it uses the current theme of the desktop.
It is possible to switch this off by calling the function win32:set-application-themed with argument nil.
win32:set-application-themed affects only windows that are created after it was called. Normally, it should be called before any window is created, so that all LispWorks windows will have a consistent appearance.
If a CAPI/Windows window is busy and unresponsive you can use the break gesture Ctrl+Break to regain control.
CAPI User Guide and Reference Manual (Windows version) - 3 Aug 2017