Hi Damien,
In the designer, right click on your MainFrameBarManager component and select "Add Detached Commandbar". It will then create a toolbar into which you can add any .NET control.The XPMenus.Bar and the XPToolBar can host objects of type BarItem only and cannot host any Controls.I have attached a sample that illustrates the same.Let me know if this meets your requirement.We appreciate your interest in Syncfusion products.
Regards,
Ebenezer.P
ToogleButton_5456.zip