Crash due opening second msa view with tree on Mac

1. Open "COI.aln".
2. Add a tree to the alignment (create a new one).
3. Close MSA View.
4. Unload tree from project.
5. Open "COI.aln" from the Project View.
Expected state: MSA Editor opens with the Tree View inside.
Bug state: sometimes (through time) Tree View opens as independent view. If you open new view for the "COI" (right click -> open in new view) in this case, UGENE crashes.