Describe the bug
Regardless what list I pick, the widget never appears on my home screen.
To reproduce
Issue is reproducible with an account from try.nextcloud.com:
Steps to reproduce the behavior:
Expected behavior
The widget should be on the home screen.
Versions
Smartphone (please complete the following information):
Are you using LDAP?
Which launcher are you using?
Default MIUI system launcher.
Does the Single Card widget work flawlessly?
Indeed, it does.
There two options for the MIUI launcher:

Tried both of them with the list widget, unsuccessfully.
Can you try steps 1-4 mentioned here please? It seems to be an issue on Xiaomi launcher only.
Tried all but the MIUI optimizations one.
To require this option whould be a major flaw, since the behavior of the system changes completly.
I'll try this option with my old xiaomi phone, since disabling the optimizations requires a reboot and affects the usability.
I'll try to get and post here a trace from the logcat after adding the widget.
Yep, in the first place it's to help us finding the root cause of the issue, it's not meant as a proper solution.
I hope to get information whether it is caused by Xiami or whether an exception is thrown (widgets are damn shitty to debug). If it works with one of those options, i can be sure that our code works actually correct, then we can try to find a workaround for xiaomi. Otherwise we will need to debug the widget (though i don't have a xiaomi device to test)...
cc @dan0xii do you have a Xiaomi device?
I couldn't find anything relevant on the logcat after trying to add the widget; only this warning, maybe it says something to you:
11-22 21:16:35.195 W/XSpaceManagerService(1637): checkXSpaceControl, from:android, to:it.niedermann.nextcloud.deck, with act:android.appwidget.action.APPWIDGET_CONFIGURE, callingUserId:0, toUserId:0
I have experience debbuging desktop software and embedded devices, but I've never worked before with android. I can try to help to debug this issue if you have any clues where to look, since it seems to affect only xiaomi phones. I've tried with a lenovo yoga book and a recent samsung phone and worked flawlessly.
@jmlgo could you please check whether the same issue appears with the "Upcoming cards" widget?
Checked. Seems to work like a charm! (v1.14.4)
Okay, we plan to rewrite the list widget from scratch (and write it like the Upcoming cards widget), so let's close this issue in favor of #767 - please subscribe to this issue to get news about the current progress. :+1: