Handle condition when child is moved to last position.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@14971 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Allow to move folders.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@14972 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Override new instance in abstract mismatch operator.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@14973 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Check for null return when new instance is called.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@14974 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Merge remote-tracking branch 'upstream'