How to catch combobox dropdown/popup event?

Hi, ALL,
This is my first post, so please forgive me for something I don't know... ;-)

On this link: http://www.opengroup.org/openmotif/docs/m214a.pdf it mentioned that you can use CBDropDownList() in order to handle combo box dropdown/popup events. However I can't seems to find out what XEvent I need to react in order to handle those events.

Can somebody help me with this? I want to catch mouse clicks as well as keyboard events...

Thank you.


Why do you need to use the internal actions? Why can't you just use the XmNselectionCallback?
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Fred K