Multiple panes in a window all show active tab the same

[lilyball]

When there's multiple panes in an Atom window (e.g. when you trigger Markdown Preview on the Welcome buffer), the active tab in each pane renders identically, making it hard to tell which pane has focus.

[probablycorey]

This is confusing! I think this is an issue with panes in general. There is an open issue about it on atom/atom#1632.