[Performance] - Forced reflows when toggling between New Game and Join Game

[YonatanKra]

It's a minor issue, but caught my eye.

When toggling between these:

There's supposed to be a nice animation, but the eventual feel is of something jumpy. Here are the performance monitoring results of this:

Note the amount of reflows involved (red lines above the charts). This results in a jumps in the animation.
I explain about reflows and animation in more details here.