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]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
universalviewer	Ready	Preview	Aug 21, 2026 4:56pm

[vercel]

@Saira-A is attempting to deploy a commit to the Universal Viewer Team on Vercel.

A member of the Team first needs to authorize it.

[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. :-)

[Saira-A]

Thanks @demiankatz. In the config builder tool hideThumbsView will disable the thumbnail view for both AV and OSD, but they work independently of each other in the config JSON files. I’ve updated the config doc so it’s hopefully clearer now but while doing so I noticed changing the following options doesn’t seem to be working in both LeftPanel and ContentLeftPanel:

     expandFullEnabled": false,
    "panelAnimationDuration": 250,
    "panelCollapsedWidth": 30,
    "panelExpandedWidth": 255,
    "panelOpen": false

Presumably they worked when I wrote the document or I wouldn’t have written to edit ContentLeftPanel to change them. Perhaps I'm doing something wrong - will look into it more next week.

[demiankatz]

@Saira-A, it's been on my to-do list for a while to revisit this PR, but I've gotten repeatedly sidetracked for the past few weeks. Did you ever have a chance to look into this further? Do you need me to investigate anything?

[Saira-A]

@Saira-A, it's been on my to-do list for a while to revisit this PR, but I've gotten repeatedly sidetracked for the past few weeks. Did you ever have a chance to look into this further? Do you need me to investigate anything?

I'm slowly going through all of the config options and noting down which ones don't work, @LanieOkorodudu is also going to double check that it's not just happening on my end and she's getting the same results. I was planning on creating an issue with a list of all of them when that's done but I suppose it wouldn't hurt to just start it off and continue adding to it as we continue with our testing. I'm also confused about what the leftPanel config is meant to be doing, it's only got 5 options and they're all repeated in contentLeftPanel.

That's a separate issue to this PR though which is finished I believe