"Group Editor" dialog is missing cancel button

[mccalluc]

Commit: 33de42c

Steps to reproduce

• Click "Collaboration" at the top
• In the "Groups" pane, click the gear beside "Public" (Or beside another group: The ability to edit the public group might be removed. See Users should not be able to remove themselves from "Public" group #1304)
• You'll get a dialog that looks like this:
  

Observed behavior

There is no cancel button, though you can hit escape, or click in the background.

Expected behavior

There is a cancel button.

[jkmarx]

@mccalluc Did you try clicking on the background?

[mccalluc]

D'oh. I had seen another dialog with a cancel, so I has expecting it here. Perhaps close this?

[hackdna]

data set sharing / collaboration

[jkmarx]

I'll add an X on the upper right corner.