>In Firefox on desktop, when I collapse a section, the gray area goes up with it revealing what was underneath.

This shouldn't be. I would to get an image of that as well.

>In Dolphin, if I set the items to be collapsed, and then log out and back in, the gray area only goes down to the bottom of the collapsed section, revealing what's underneath. It appears to be a failing in the mobile version that the gray area does not auto-resize after collapse. It does auto-expand.

That might be fixed. It seems the proper height cannot be determine so I might have to take a look at that.