i think there is some mistake in event wiring.. i cannot tell much, because i don't understand the glamour models.. but what i found strange is that i get large pause before i got halt in actOnMatchingPresentationsChanged: it looks like the same event goes twice (or there two kinds of events) and you model tries to update the detal list bypassing (or in addition) to the #actOnMatchingPresentationsChanged: To reproduce my observations try do following: - evaluate the doit which you gave above , so you have two windows open. Now click in a browser list, to set the initial selection. Now go to #actOnMatchingPresentationsChanged and put halt there actOnMatchingPresentationsChanged: anAnnouncement +++ self halt. GLMWatcherWindow uniqueInstance addContent: [ self renderObject: anAnnouncement pane ] Now click on list again to change the selection. You can observe a huge pause before you got halt. So, apparently the logic in #addContent: has nothing to do with the blocking you still observe. (btw in image which you give in link the morph generation is still inside of #addDeferredUIMessage, i , of course moved it outside before trying things). P.S. btw, did i told you that i don't like #suspendAllWhile: in announcer? :) The point is: if you need things like that, then you doing something wrong. -- Best regards, Igor Stasenko.