Notes:
That property is independant on EnableTextEditingOnAdd and text of any ContentTabItem can be edited.
Client events EditingStart and EditingEnd can be used to control editing.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2