*Steps to reproduce:*
# Create a URP 3D Project
# Create an Animator Controller and open it
# Create an empty State and select it
# In the Inspector for that State, try and pick a Motion with the circle to the right of the Motion field

*Actual results:* Warning "Unknown pseudo class "multiline"
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)" logged everytime you pick a Motion, after picking it, the Warning will also log when entering Play Mode or importing the Asset

*Expected results:* No Warning is logged

*Reproducible with versions:* 6000.0.28f1, 6000.0.34f1, 6000.1.0b3

*Not reproducible with versions:* 2022.3.56f1, 6000.0.27f1

*Tested on (OS):* Windows 11