I make this property to BorderStyle.None and it works perfect in Windows XP, but when I change to Vista, it's always "inset". Is it a new bug on ver 2008 vol.2?
Besides, there is no way to change the mdi client's color. I the the custom color in Word 2007, not the AppWorkspace color. How can I change it?
The border style issue sounds like a bug. I would recommend submitting it to the support group: http://ko.infragistics.com/gethelp.
The UltraTabbedMdiManager does not let you change the MdiClient control's back color. You can try to walk down the Form's child controls and change it manually, but I haven't tried this.