Some resources do not have the tab button to show the TOC. See image below.
All resources have it, but looks like in the ISBE your locator bar is turned off. Click in that pane somewhere to bring the focus there, and then press Ctrl+Shift+L and it will come back on again.
There seems to be an intermittent bug where the locator bar mysteriously gets turned off in some resources when the user does not remember doing it on purpose. It might just be user error, but some of us who are pretty experienced with Logos have noticed this too, so there might be a bug lurking. That's been reported elsewhere.
Wow, I even knew that was there just never paid attention. I feel dumb! Thanks Mike![;)]