Comment 2 for bug 789510

Could you check if the memory leak is still an issue with Unity 3.8.14 ? Upgrade to the latest version of Compiz through update-manager as well to check it out.

As for the panel hiding, the panel is never supposed to hide when you maximize an application. It will always stay at the top of the screen. (Did you mean "launcher" instead of panel? The launcher is the pane at the left of the screen).