[LH3244] Binder/Editor selection bug

Editor changes without selecting a document.

To recreate: have two Editors open displaying two different documents, say LEFT and RIGHT.

In Binder, click on RIGHT while the right editor is the active one.

Now click over to left Editor to make it active.

Now click anywhere in binder, but not on a document. Say, in the blank space below Trash.

The left Editor now displays RIGHT instead of LEFT.

This has been filed. Thanks for the reproduction steps, that made this one an easy one to track down!