Hi,
We can change the size of the PopupContainer to that of the GridGroupingControl in the BeforePopup event of the Popupcontainer.
void PopupContainer_BeforePopup(object sender, CancelEventArgs e)
{
this.comboDropDown1.PopupContainer.Width = gridGroupingControl1.Width;
}
Please have a look at the sample attached and let me know if you need any further assistance.
Thanks for your interest in Syncfusion products.
Regards,
Golda
combodropdown0.zip