roof break tool doesn't work for me!!

[wayneriley]

Hi! haven't used my drawing program for a while. trying to do a quick drawing and cant seem to get my edit button to break a roof plane for me. When i click on the roof plane where i want the break ,hit the edit button and hit the roof plane again the break line doesn't show up??! wall break seems to work fine! anybody know what i might have turned off or am doing wrong!! weird! thanks guys.