[Solved] I want to customize Combobox dropdown button(arrow goes up or down)

[Jinny]

Hi,

I'm using a customized style for RadCombobox.

The problem is, I found it impossible to reverse the dropdown button(arrow) when it is clicked.

I want the arrow to go up when the combobox expands and go down when the combobox collapses.

 

Can Anyone give me an example code of this?