[Pharo-dev] Case 13007 Cannot-integrate-a-slice-with-monticello-red-square-in-the-UI

[Ben Coman]

Priority 2 fix ready for review. Please come pick it apart.
https://pharo.fogbugz.com/f/cases/13007/Cannot-integrate-a-slice-with-monticello-red-square-in-the-UI
cheers -ben