Aside from the fact that this issue is filed on the pharo instead of the moose bugtracker 14858 <https://pharo.fogbugz.com/default.asp?14858> Hangup when rendering TRLabelShape with SmallInteger instance as text I wonder why the error locks the UI. I can see a RMOD, maybe Trachel should stop any attempt for rendering if the Morph has the #errorOnDraw property set? nicolai