Fluidify event based extension code navigation

[D8H]

Restore the events scrolling offset

When switching between functions, the events scrolling offset is reset. This can be particularly annoying when doing back and forth between 2 functions to try to understand how a code work or just wanted to do a copy-paste.
The same thing happens with JavaScript events.

Collapse extension sub-panels

It could be interesting to be able to collapse and expand "Function configuration" with an arrow button to get more space to see the events.
Same for "Functions", "Behaviors" and "Behavior Functions" to have more space for one of the 3 when there is a lot of functions.

Call tree view

In big extensions, there can be some depth in the call tree and it can be hard to have the big picture without some visualization.
For private functions, the callers can be listed in the description, but this is less practical.