UxmlElementAttribute not found inside managed plugin?

[Alex-Chouls]

I’m trying to put some custom controls in a managed plugin, but I get this error: “[customcontrol] is missing a UxmlElementAttribute and has no registered factory method. Please ensure that you have the correct namespace imported.”

The custom controls no longer show up in the UI Builder and fail to load from uxml files.

It seems like the UIToolkit.SourceGenerator is not finding the UxmlElementAttribute when it’s in a managed plugin? Is this a known issue or am I doing something wrong?

[Spy-Master]

UI Toolkit Serialization and Library Compilation (dll support)

Hello! Here is a tip for those who want to continue building their VisualElements into libraries (dll). UI Toolkit now uses a code generator via UxmlElement to support UXML serialization. When compiling custom elements into DLLs, you might have encountered issues with elements not appearing in the UI Builder or failing to serialize correctly. This problem occurs because the generated serialization code isn’t included in the DLL. To resolve this, you need to run the UI Toolkit Source Generator …