Add configuration option to hide thumbnails view on left panel

[Saira-A]

{ "modules": { "contentLeftPanel": { "options": { "hideThumbsView": true } } } }

The addition of a hideThumbsView config option allows the thumbnail tab to be hidden from the left panel for OSD and AV manifests, so that only the index tab is visible within the panel.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
universalviewer	Ready	Preview, Comment	Jul 21, 2026 3:27pm

[vercel]

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[demiankatz]

Thanks, @Saira-A, I see this is working as expected in OSD mode.

I tried with this MediaElement manifest, and the thumbnails did not go away: https://digital.library.villanova.edu/Item/vudl:283833/Manifest -- same thing with this multi-part PDF manifest: https://digital.library.villanova.edu/Item/vudl:294631/Manifest . That is probably for the best, since in both cases there is no index tab, and hiding the thumbnails would make content inaccessible. But I'm not sure where to find a relevant AV example to test.

Also, one request: we should update the config options documentation when adding a new config option. Might as well do that as part of this PR so we don't forget!

[Saira-A]

Thanks @demiankatz, I've added it to the config doc. We need it for AV and I added it in for OSD at the same time just in case it's useful but as you mentioned I'm not sure if there's much benefit to adding it for any other formats. If there's no index then it will leave an empty left panel but that can be disabled in the config already

[demiankatz]

A couple of questions:

1.) This seems to be filed under leftPanel in the documentation, but it's actually set in contentLeftPanel in the code. This is extra confusing because the documentation doesn't seem to have a contentLeftPanel section, yet several of the leftPanel settings have notes I don't fully understand referencing contentLeftPanel. Is something wrong or am I just confused?

2.) Is there a way to disable thumbnails for ONLY AV manifests but not OSD manifests? This seems like a use case that might crop up, but I have a feeling it's not currently possible. I'm certainly willing to approve this as-is if it's the best we can do within the limitations of the config system -- but this whole review process is reminding me of how frustrated I am by the current config system. Wish I had time to try to make it better, but I guess we have to choose our battles given limited resources. :-)