Sets whether the dropdown button of the combo box should be always sensitive (GTK_SENSITIVITY_ON), never sensitive (GTK_SENSITIVITY_OFF) or only if there is at least one item to display (GTK_SENSITIVITY_AUTO). Since 2.14
specify the sensitivity of the dropdown button
See Implementation
Sets whether the dropdown button of the combo box should be always sensitive (GTK_SENSITIVITY_ON), never sensitive (GTK_SENSITIVITY_OFF) or only if there is at least one item to display (GTK_SENSITIVITY_AUTO). Since 2.14