AnchorDocking: SimplifyOneControl destroy the layout

Original Reporter info from Mantis: Michl @michl1

• Reporter name: Michl

Description:

When SimplifyOneControl has more then one control in it, the layout got destroyed.

Steps to reproduce:

See added layout for miniIDE.
Close ObjectInspector, see destroyed layout.
-> save it and load it, then you got a exception

Mantis conversion info:

• Mantis ID: 34937
• Build: 60121
• Version: 2.1 (SVN)
• Fixed in revision: 60206 (#3d405210)
• Target version: 2.0