ReadOnly specifies whether the user will be allowed to modify the contents of the control. However note that the user will be allowed to enter the edit mode and select and copy part of the contents.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, 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