TTMSFNCToolBarItemPicker.DropDownControl Property
Custom control to embed inside the button's drop-down popup. Assign any
TControldescendant to show a custom picker or panel.
API unit family: TMSFNCToolBar
Declaring type: TTMSFNCToolBarItemPicker
Inherited from: TTMSFNCToolBarButton
Type: TControl
Syntax
property DropDownControl: TControl;