Floating Material Preview window has a burger icon button that does nothing when pressed

Steps to reproduce:

1. Create a new Unity project using the Universal 3D template
2. Create a new Material (Assets > Create > Material)
3. Select the created Material in the Project Browser window
4. Press the burger icon button in the Material Preview section in the Inspector window
5. Select "Convert to Floating window" option
6. Click the same burger icon button in the Floating Material Preview window
7. Observe the Floating Material Preview window

Actual results: There are 2 burger icon buttons in the Floating Material Preview window and one of them does nothing when pressed

Expected results: Either the burger icon button does not exist like before regression, or the burger icon button opens a dropdown

Reproducible with versions: 2023.2.0a19, 6000.0.53f1, 6000.1.11f1, 6000.2.0b9, 6000.3.0a1

Not reproducible with versions: 2022.3.64f1, 2023.2.0a18

Tested on (OS): macOS Silicon Sequoia 15.5, Ubuntu 24.04