Joseph, you might want to check whether your modules have caching enabled (in module settings). If the module is cached, code behind is not hit at all. You can prevent a module being set to caching by changing the default cache time in module definitions to -1

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I have a slightly similar issue with 4.9 in VS2008 except that my IMC event does work (regardless of the cache default time).

In 4.5 my IMC Select Module posted the selection details event to the Listening module which then picked up the value and displayed the details correctly in the Listening module text fields.

In 4.9,  the IMC Select Module event works correctly with  the Listening module picking up the event as well. The Listening Module then moves the data to the display fields but nothing gets displayed by this Listening module and all of the fields remain blank in the display even though I know the text fields have the data held in them! There is now no rendering taking place of this Listening module following the incoming event, whereas 4.5 used to.

[Re-edited] I now have a 2nd example of an IMC event working perfectly under 4.5 but which now doesn't work under 4.9, giving exactly the same blank result in the Listening module.   

(Incidentally, I also run in Edit Mode at the moment)