Root VisualElement's size is always 0

Unity Engine
1

Hello,

I have an issue with my root. I use single UIDocument with single PanelSettings:
6217125--683562--upload_2020-8-18_10-9-40.png
and I spawn all panels inside its root VisualElement (which only has align/justify and flex-grow set).
In an empty scene everything renders well - root object (VisualElement UI Panel Settings) has its width and height set to 1920 and 1080.
However when I put it in the actual game it suddenly stops working - root’s width and height are just 0.

In the game the GO with UIDocument is instantiated and put inside another GO in DontDestroyOnLoad - I wonder if that may be an issue? Or is it some issue with the ThemeStyleSheet on PanelSettings?
I can’t find any ‘best practices’ concerning the setup of PanelSettings, UIDocument or something like that.
I would appreciate any help with that issue.

2

Ok, nevermind, issue fixed - I forgot to add the EventSystem for UIToolkit.
This is quite unintuitive that we have 0 feedback in the Editor that the EventSystem is missing and that the UI is not rendered without it.

3

We’re aware. It should be like this long term.