Icons visible when opening document from Favorites page

Nextcloud version (eg, 10.0.2): 11.0.1
Operating system and version (eg, Ubuntu 16.04): Debian 8.6
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.10
PHP version (eg, 5.6): PHP 5.6.29
Is this the first time you’ve seen this error and can you replicate it?: Yes

The issue you are facing:
When going to the Favorites (where I have 2 spreadsheets), and select a document to open in Collabora Online, it shows the icons on top of the Collabora section:

When going to the actual folder where the documents are, and then open it, the icons don’t show.

Can somebody confirm this? This is the first time I used the Favorites features and just bumped into this strange behaviour.

Just to add to the sequence of steps:

  1. Go to favorites:

  2. Click on document (in this case Calendar 2017). The menu to the left disappears:

  3. Collabora starts (with blank grey page first):

  4. Collabora opens document and icons still visible:

I tried this also with default theme to make sure it wasn’t caused by my own theme.

Nobody can confirm this? I am just curious if this is a single incident or a common problem.

Has nobody been able to confirm (or even dispute) this issue that I am seeing? It only happens on the Favorites page. I have even rebuild my NextCloud server from scratch and it still is happening.

I am wondering if I am the only one using the Favorite feature together with Collabora. Has nobody got this issue with the icons remaining visible when editing from the Favorites view?

I am now on 11.0.2 and issue is still there. On my own theme and also on the default theme even with a hard reload.

I have been able to resolve it by patching the iframe from Collabora.

I have changed the following line in /apps/richdocuments/js/viewer/viewer.js on line 105:

var $iframe = $('<iframe id="richdocumentsframe" style="width:100%;height:100%;display:block;position:absolute;top:0;" src="'+viewer+'" />');

to

var $iframe = $('<iframe id="richdocumentsframe" style="width:100%;height:100%;display:block;position:absolute;top:0;z-index:5;" src="'+viewer+'" />');

I also raised an issue on GitHub for this.