(Spec/Morphic) MorphTreeNodeMorph>>setSelectedSilently: does not seem to select silently.

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