*Steps to reproduce:*
# Create a new Unity Project
# In the Hierarchy, add a UI Document GameObject
# In the Project window, create a new UI Document (UXML) via Assets > Create > UI Toolkit > UI Document
# Open the UXML in the UI Builder
# Make some changes in the UI Builder (e.g. add a button) without saving
# Enter Play Mode
# While still in Play Mode, maximise the UI Builder window and then return it to its previous size
# Alternatively, attempt to make edits in the UI Builder while in Play Mode
# Observe the Console for warnings

*Actual results:* A warning appears in the Console: " UI was recreated and no companion MonoBehaviour found, some UI functionality may have been lost.
UnityEngine.UIElements.UIElementsRuntimeUtilityNative:UpdatePanels () (at /Users/bokken/build/output/unity/unity/Modules/UIElements/Core/Native/UIElementsUtility.bindings.cs:21)"

*Expected results:* UI Builder should not throw warnings when editing unsaved changes in Play Mode

*Reproducible with versions:* 6000.2.0b1

*Tested on (OS):* macOS 15.5 (Silicon M4), Windows 11

*Notes:*
*  A UI Document GameObject must be present in the Hierarchy during Play Mode
* This issue may confuse users and hinder iterative UI development workflows