Hi Kenny, So I'm cleaning up my celtk stuff so I've got a list of wee things that cause problems when asdf installing it that I'll submit patches for over the next few days. Here's the first... slot-value-observe seems to take an extra parameter now so I've adjusted my version to the following. Is this ok to be checked in? (defmethod slot-value-observe progn (slot-name (self tk-object) new-value old-value old-value-boundp cell) (declare (ignorable old-value cell)) (when old-value-boundp ;; initial propagation to Tk happens during make-tk-instance (bwhen (tco (tk-config-option self slot-name)) ;; (get slot-name 'tk-config-option)) (tk-configure self (string tco) (or new-value "")))))