Function event: Using function inside function only possible after using it in event

[Wend1go]

Describe the bug

When you try to run a function inside another function it won't get shown in the actions list until you have previously used it in a normal event outside of the function event.

To Reproduce

1. Create a project and add a function extension "myfunctionextension"
2. Add a function "func1" to myfunctionextension
3. Add a function "func2" as an action in myfunctionextension
4. Add an event in func1 and try to add func2 -> it doesn't appear in the list of actions under myfunctionextension
5. Close the myfunctionextension tab (if you open it will appear)
6. Go to the scenes event sheet and open add actions -> func2 appears there
7. Add func2 to the scenes event sheet
8. Open the the myfunctionevent tab again and add func2 in func1 ->it appears at last

[4ian]

So this is because "extensions" corresponding to functions are re-generated and reloaded each time you focus another tab.
This is because generating functions and loading them can be a bit costly (a set of functions with really long events sheet of ~500 events each could reach a few seconds). This would be an exceptional situation but still, I make sure to avoid regenerating the functions too often.

I think an improvement would be too also do this when:

• you navigate to another function (so that func1 can use func2 or vice-versa)
• a parameter is changed in a function (so that a function can call itself and is properly appearing in the list of actions/conditions, even if you've not navigated to another function/tab in the meantime).