Using a mouse scroll wheel on a Motif option menu

Question

I have a Motif XmRowColumn set up as an option menu (XmMENU_OPTION).

When you scroll the mouse wheel while over the opened list of options, the button your cursor is over is chosen and the list closes.

I need to be able to use the mouse scroll wheel on the opened list of options: the selected option changes (like using the up and down arrow keys), but the selection is not chosen and the list does not close.

So far I have two stumbling blocks:

1. I have not been able to stop the list from closing when Button4 (scroll forward) or Button5 (scroll backward) is pressed, except to freeze the application to input:

   On both the XmRowColumn widget, and the widget for the cascade button, I've tried overriding the translations for <Btn4Down>,<Btn4Up> and <Btn5Down>,<Btn5Up> to do nothing, but scrolling over the list still selects whatever button the cursor is over and closes the list.

   I've tried ./<myApp> -xrm "*translations:#override <Btn4Down>,<Btn4Up>: do-nothing()", but then when I scroll the wheel forward over the list the application freezes until I hit Escape.

2. I'm unclear on how to make the 3D-effect-ed button switch to the next/previous button. I haven't made any progress on this step, because I can't get the list to stay visible while still handling user input.

What widget(s) should I be overriding the translations of? What functionality is there to control which button in the list has the 3D-effect?