Improve ability to change view/window widths

[gr5]

This video, built on pull request #263 shows an issue:
https://www.youtube.com/watch?v=wvbl5Mw1j3g

So here's the problem as I see it. I set the right panel to an overly agressive minimum width (I think it was 200 pixels) in a recent PR. And I like that it can go that small. But it shouldn't stay there so easily when there is plenty of room.

So the request:
Make the right most panel larger by default but still allow it to get crazy skinny when needed (e.g. user wants to make other windows larger or the display resolution of their monitor is very tight.