Hi Remigio
Thank you for contacting Syncfusion Support.
We have checked the reported scenario with RibbonControlAdv and we were able to observe that the MergeTabInfo instance hold on switching the forms[tabs] at our end. We have logged a defect report on this and the fix will be available in our upcoming 2018 Volume 4 release which is expected at end of December 2018.
Regards,Arulraj A