To reproduce: Me.RadDock1.DocumentTabsAlignment = Telerik.WinControls.UI.TabStripAlignment.Left Me.RadDock1.DocumentTabsTextOrientation = Telerik.WinControls.UI.TabStripTextOrientation.Vertical Please refer to the attached file. Workaround: Me.RadDock1.DocumentTabsAlignment = Telerik.WinControls.UI.TabStripAlignment.Left Me.RadDock1.DocumentTabsTextOrientation = Telerik.WinControls.UI.TabStripTextOrientation.Vertical For Each d As DocumentWindow In Me.RadDock1.DockWindows.DocumentWindows d.TabStripItem.AngleTransform = 180 Next Or: foreach (DocumentWindow d in this.radDock1.DockWindows.DocumentWindows) { d.TabStripItem.FlipText = true ; }