Wouldn't it be easier to just ... ?

if (center.equals(newCenter)) { 
  this._enforcingBounds = false;
  return this;
}

Sure, it's a matter of taste I guess.

Personally, I like try-finally to avoid the duplicate flag reset (it must be reset for normal exit as well) and also always making sure the flag is reset no matter what , even if something throws an exception in there, but I guess the advantage of that can be debated.

It might be that try-finally is more common in C#/Java. It appears this is the first time finally is used in Leaflet, so perhaps better to do it your way?

Even if the try/finally is more elegant, afaik it's not optimizable (see https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#2-unsupported-syntax for example), so I'd duplicate the reset as for now.

Ok, removed the try-finally, hope this looks alright now!

@yohanboniface interesting point regarding optimization, will keep that in mind (although this code is not on any performance critical path, as I understand it).

Nice turnaround :)