I have a basic plugin admin options panel for events. I want to call a function that is from a different social media plugin (Mingle). I can call Mingle plugin functions in the theme, but not within core files of other plugins, or other plugins' admin panels it seems.
I have tried including the other plugin's files, adding a hook to the theme functions file, add_action, add_filter, init etc. But I do not know what the first argument for those actions would be, since I want the function inserted into a specific admin page from another plugin.
The only solution that has worked is merging the code of the two plugins, although it seems odd that there is not a simpler method.