All tabs disappeared after normal close of chrome

I've only been using this extension for a couple of days, so maybe I did something wrong. I quit chrome, then restarted it a couple of hours later. There are no tabs at all on the Tabs Outliner screen. I have no idea what I did to cause this, so I don't know what to do to fix it. I think I can probably get things going again by uninstalling and reinstalling the extension, but I don't want to reinstall unless I know how to avoid causing this to happen again.