Un-hide track in mixer window

This is probably a reeealy dumb question, but how does one restore display of a track strip in the mixer window once it’s been hidden (ie, by clicking the upper right [X] button)? Tried right-clicking various places, Google, Ardour manuals – probably right in front of me… This is on Ardour version 3.5.403 on Fedora 21 with KDE.

If you move your mouse to the left side of the mixer window a double arrow will appear. Left click on the double arrow to move the mixer strips over to reveal a list of mixer strips with a checkbox to select which mixer strips to show. Check the one you want to show.

Ah yes, I see it. Thank you Edward!! As I predicted, right in front of me!