video:  [IMG_7840.mov]

When a label is selected, other labels in the same thread highlight in yellow:

I added a "search" label to the floor:

which brings up a text box on the kiosk computer, where you can type in a search term.  Currently searches in "from" and "subject" fields.  

Results are highlighted in red.  Here's everything by Toby:

When a search is active, the "reset" portion of the search label highlights.  Point at it to clear the search.