On Microsoft Windows XP, Vista and Windows 7 LispWorks is themed . That is, it uses the current theme of the desktop.
It is possible to switch this off by calling the function
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.
CAPI User Guide (Unix version) - 30 Aug 2011