Hi, I had some problems with TreeModel>>deselectAll. It appears that when one sends #deselectAll, the selectedItemsChanged block is passed a _non-empty_ selection. While debugging I saw that #setSelectedSilently: apart from setting a #selected instance variable, also sends #selected: to its “complexContents”, which triggers an Announcement chain causing the bug in the previous paragraph. When removing this statement from #setSelectedSilently: it seems to work properly. However I don’t know if this “fix” of mine has any side effects causing it to break at other parts of UI code which is not using Spec. I opened an issue on fogbugz: https://pharo.fogbugz.com/f/cases/17391 Thanks