Be able to see and modify (some) scene aspects while on the eventsheet

I dont like to go back to the scene just to modify a single aspect in my object/modify the value of a scene variable to then return to the eventsheet.

When going to a eventsheet, tabs like the object/object groups list should remain there, toggleable by buttons, and when going to a external event, the object/object group list of the scene they are linked with should also be present there, also when clicking on the top-right button, the one that we use to choose which scene the external event is linked with, there should be a button that opens the scene variables of that scene, without the need to go back to the scene.