I am not even sure how they managed to do that. Standard Cocoa controls all do this by default. Windows are resizable, fullscreen mode works by and ‘source lists’ (sidebars) can be widened. They must have purposely prevented all those things, haphazardly. :/
But why should they do that? It's such a stupid crap. Seems someone forgot to work on it. Did the version number even change since the first beta of 10.11(.0) I never looked at it.
Edit: I have the old one too, but it's from Yosemite and I don't know if it could cause a damage.
Installing the Delta Update on top of the patch changed nothing. It does not even recognize that there was an update, sending data to Apple was still turned off. That's what I always do first after an update and did it already after the patch.