[Lazarus] Getting notified when active editor changes

[Ondrej Pokorny]

On 03.08.2024 15:11, Michael Van Canneyt via lazarus wrote:
> I implemented an initial version of this new feature, I pushed it to 
> the git repo.

I always wanted to do this for the project inspector. So I used your 
approach as an inspiration :)

I also found out that LazarusIDE.RemoveAllHandlersOfObject doesn't 
remove the SourceEditorManagerIntf events. I fixed that in your code.

Ondrej