*Steps to reproduce:*
# Create a new Unity project using the Universal 3D template
# Create a Cube GameObject (GameObject > 3D Object > Cube)
# Open the Animation window (Window > Animation > Animation)
# Create a new animation
# Open the Animator window (Window > Animation > Animator)
# Dock the Animator window
# Close the Editor
# Repeat step 1
# If Animator window is not opened, repeat step 5
# Click the "eye" button in the Animator window to hide the Layers and Parameters tab
# Click the dropdown button next to the "eye" button in the Animator window
# Observe the Console window

*Actual results:* "MissingReferenceException: The variable m_AnimatorController of AnimatorControllerTool doesn't exist anymore." error is thrown

*Expected results:* The dropdown should not be in the Animator window and should not throw any errors

*Reproducible with versions:* 2021.3.51f1, 2022.3.62f1, 6000.0.50f1, 6000.1.4f1, 6000.2.0b3

*Tested on (OS):* macOS Silicon Sequoia 15.3