Fixes #8478: if a StackContainer child is selected, then deleted, then readded, it will have both the dijitVisible and dijitHidden CSS classes applied.
Fixes #8478: if a StackContainer child is selected, then deleted, then readded, it will have both the dijitVisible and dijitHidden CSS classes applied.

Still unclear what should happen when I remove the child; I guess both CSS classes should be removed?  For now just put a safeguard in _setupChild().

!strict.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@16557 560b804f-0ae3-0310-86f3-f6aa0a117693

redaktor/deliteful