Some menus / selection boxes need scroll bars

Some of the menus are a bit too tall, especially when working with a smaller monitor.

And if you add too many "set" nodes in your shader, I suppose eventually the menu for the "Get" node would be so tall, you couldn't see all the options anymore.

Probably need to add a scroll bar to some of these menus, and make them smaller by default, and just let us scroll to get to all the options. This would also make it feasible to add a lot more nodes, without worrying about the selection box getting taller than the screen can fit it.