Flex :: ComboBox Click Event Conflict With Its Container?

I want change the HBox's style when click any object inside this HBox. I set handle for click event of HBox, and then I found it very difficult to select item in the combobox in this HBox.When I click the combobox, it drops down its item list, and HBox style changed, then combobox drop up very quickly, I have no time to select an item in the Combobox.Here is my codes, is there any way to avoid this problem?

<mx:Repeater id="itemRepeater">
<mx:HBox id="itemHBox" styleName="active" click="onItemClick(event);">
<mx:ComboBox id="cb1" dataProvider="{dp}" close="closeHandler(event);"/>

[code].....