Extend the community picker when making a post?

Currently when you go to pick a community when making a post it only shows 4 communities, I feel like this could be extended so the user can see more communities at one time.

Also a lot of Android phones have a nifty little pop up list type thing that can be built into some apps or sites, I can attempt to get a screenshot if wanted I just can't think of any site or app that uses it off the top of my head.