fix [#35178] Autoselect-in-list for Vertex Group selection doesn't work.
disallow assigning values that don't exist into a text field with a search-box.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56465 954f8c5b-7b00-dc11-b283-0030488c597c