property ComboBox.DropDownButtonWidth as Long
Retrieves or sets the width, in pixels, to display the drop down button of the control (including the clear-button).

TypeDescription
Long A Long expression that specifies the width to display the drop down button.
By default, the DropDownButtonWidth property is -1, which indicates that the control's ScrollWdth property specifies the width of the drop down button. In other words, if the DropDownButtonWidth property is negative, the width of the drop down button and the vertical scroll bar are the same. If positive, it indicates  the width, in pixels, to display the drop down button of the control. The property has effect only if the control's Style property is DropDown or DropDownList. Use the HideDropDownButton property to hide the control's drop down button when the control loses the focus.