Hi, Elakkiya.
Thank you for the quick reply.
According to the documentation, the ToolStripMenuItem is a menu item for ToolStripDropDownButton in the RibbonControlAdv.
Unfortunately that's not the case.
We do not use the RibbonControlAdv, actually, we use a SplitButton on the form close to a text box (see image below) and the items for SplitButton are toolstripitem as described in the code previously. Also, if changed to ToolStripMenuItem the code does not compile.
Please let me know if you need more details.
Regards.