Well, considering there is no "shift+alt+click" command standard in Max, you might consider other sources for the conflict. What OS? Third party apps running in the background? Which external are you using?
At the very least did you remove the alt+click entry in the config file to see if it resolved the problem? Not to mention that it's an external built for Max.. perhaps contacting the creator might help.
All pretty standard in terms of troubleshooting...
Where MetaMax said it is. In the Max folder: Cycling '74/interfaces/maxinterfaces.json
Thing is, I think the "option-click on object to open its .maxhelp file" thing is hard-wired. (At least, I've never seen where it can be configured, either in the interfaces/ folder or in the init/ folder. And those are the two obvious places.)
On some versions of Max, option-click may be "greedy" (i.e., match if any additional mod keys are held at the same time, for isntance, your shift-opt-click on Mac, or shift-alt-click on Windows.)
It would still be a lot more helpful if you'd tell us what version of Max you're running and on what platform. We're not bloody mindreaders, and everything else is stabbing in the dark.