ui.backend.windows: fix compile error in ui-wndproc
ui.backend.windows: fix compile error in ui-wndproc

kingcons/factor,erg/factor,erg/factor,kingcons/factor,erg/factor,mcandre/factor,mcandre/factor,kingcons/factor,mcandre/factor,mcandre/factor,kingcons/factor,erg/factor,erg/factor,mcandre/factor,mcandre/factor,erg/factor,erg/factor,mcandre/factor