Steps to reproduce:
1. Create or open any Project
2. Create an Animator Controller Asset and open it
3. Undock the Animator Controller Window
4. Dock the Animator Controller Window
5. Undock the Animator Controller Window
Actual results: Error "Assertion failed on expression: '!dest.m_MultiFrameGUIState.m_Windows'" is logged when Docking or Undocking the Window after the first time it's Undocked
Expected results: No Errors are present when docking or undocking Windows
Reproducible with versions: 6000.3.0a1, 6000.3.0b4, 6000.4.0a1
Not reproducible with versions: 6000.0.59f1, 6000.2.6f1
Tested on (OS): Windows 11, macOS 15.6.1