Hi Nick,
Extremely sorry for the delay in getting back to you.
The reported query “Borders in the PanelItem of a Syncfusion.Windows.Forms.Tools.RibbonControlAdv” was an known issue in 11.1.0.21 version and has been fixed in our current source. Please refer incident 106514 for the patch details.
Please let us know if you have any concerns.
Regards,
Paul Anderson S