UI Builder preview 12 errors in 2020.3.0f1

I am attempting to install the latest version of UI Builder (which is listed as 1.0.0-preview.12 on https://docs.unity3d.com/2020.3/Documentation/Manual/com.unity.ui.builder.html as of this writing) using the Package Manager in Unity 2020.3.0f1

When I install 1.0.0-preview.12 in a clean project I get the following errors:

Code (CSharp):

1. Library\PackageCache\com.unity.ui.builder@1.0.0-preview.12\Editor\Utilities\StyleField\FieldSearchCompleter.cs(482,38): error CS1061: 'ScrollView' does not contain a definition for 'horizontalScrollerVisibility' and no accessible extension method 'horizontalScrollerVisibility' accepting a first argument of type 'ScrollView' could be found (are you missing a using directive or an assembly reference?)
2.  
3. Library\PackageCache\com.unity.ui.builder@1.0.0-preview.12\Editor\Utilities\StyleField\FieldSearchCompleter.cs(482,69): error CS0103: The name 'ScrollerVisibility' does not exist in the current context
4.  
5. Library\PackageCache\com.unity.ui.builder@1.0.0-preview.12\Editor\Builder\Inspector\BuilderInspectorAttributes.cs(242,39): error CS1061: 'ScrollView' does not contain a definition for 'horizontalScrollerVisibility' and no accessible extension method 'horizontalScrollerVisibility' accepting a first argument of type 'ScrollView' could be found (are you missing a using directive or an assembly reference?)
6.  
7. Library\PackageCache\com.unity.ui.builder@1.0.0-preview.12\Editor\Builder\Inspector\BuilderInspectorAttributes.cs(242,71): error CS0103: The name 'ScrollerVisibility' does not exist in the current context
8.  
9. Library\PackageCache\com.unity.ui.builder@1.0.0-preview.12\Editor\Builder\Inspector\BuilderInspectorAttributes.cs(250,39): error CS1061: 'ScrollView' does not contain a definition for 'verticalScrollerVisibility' and no accessible extension method 'verticalScrollerVisibility' accepting a first argument of type 'ScrollView' could be found (are you missing a using directive or an assembly reference?)
10.  
11. Library\PackageCache\com.unity.ui.builder@1.0.0-preview.12\Editor\Builder\Inspector\BuilderInspectorAttributes.cs(250,69): error CS0103: The name 'ScrollerVisibility' does not exist in the current context

This does not occur with Version 1.0.0-preview.11

 

I'm experiencing the same issue. Should we be using a different package/version with 2020.3?

 

If you doubleclick on the errors, you can see that it has to do with preprocessor directives which account for version 2020.1 and 2020.2 but not 2020.3 and it falls back to code for Unity versions 2019 and below, causing errors.

Unfortunately, changing the code manually does nothing as the changes get reverted automatically.

 

It seems that removing and reinstalling the UI builder package fixed the errors for me.

 

... until you restart the editor

 

Whoops! It seems they're aware of the bug (I saw another thread mentioning it) so hopefully they'll push a fix soon.

 

Hmm... downgrading to preview 11 and then upgrading again resolves the issue for me, even after restarting.

 

Not for me. The same exact errors are still there.

 

Might this also be the issue that's stopping me from searching for VisualElements within a TemplateContainer? Previously, after I had cloned the asset tree, all Visual Elements were queryable as if they had been included in the single UXML document, instead of an included Template. I'm just deciding whether I should be spending time on a workaround, or if the new package you mention should resolve this.

 

I can confirm this errors are gone now. But another one still remains (was mentionioned in another thread, I think but I could't find it):

error CS1503: Argument 1: cannot convert from 'UnityEngine.Sprite' to 'UnityEngine.UIElements.Background'

When opening Unity.
it dissapears when the code is compiled once.

 

it is in our own code, but there is no error.

Code (CSharp):

1.  
2. public void SetPicture(Sprite image)
3. {
4.        pictureElement.style.backgroundImage = new StyleBackground(image);
5. }

This line throws the error.
But When I open the script in Visual Studio. it shows no error there, since there is a constructor for StyleBackground with a Sprite as parameter.
When the code is compiled once, the error is gone in Unity

 

Yes it is. I just didn't find the thread