How to change the size of the combo box Button

Change the size of the combobox button by changing the ButtonBarSize in the CellModel for the control.

//Creates Combobox Cell model object.
GridComboBoxCellModel model = this.grid.Model.CellModels["ComboBox"] as GridComboBoxCellModel;

//Assigns a new value to its ButtonBarSize property. 
model.ButtonBarSize = new Size(8, 8);
'Creates Combobox Cell model object.
Dim model As GridComboBoxCellModel = CType(Me.Grid.Model.CellModels("ComboBox"), GridComboBoxCellModel)

'Assigns a new value to its ButtonBarSize property.
model.ButtonBarSize = New Size(8, 8)