Hi Ryan,
Thanks for your interest in Syncfusion products.
You can set the bounds for the dropdown button by overriding the UpdateDropDownButtonBounds method of combodropdown Class. Please refer to the attached sample in the following location and let me know if this is helpful for you.
http://websamples.syncfusion.com/samples/Tools.Windows/F58738/main.htmBest Regards,
Poly