[ComboBox] if you click on uneditable comboBox it closes and opens immediately.

See attached movie. There you can see comboBox on the left and choiceBox in the right half of movie. I tried to show, that if you click on choiceBox, when dropDown is opened, then dropDown will be closed.
But if you click on comboBox, when dropDown is opened, then it will be closed and opened immediately (flash).