Reproduction steps:
1. Create a new blank 3D project
2. In the Scene view, in the tool overlay at the bottom left, press the "Cameras" button
3. Drag the opened window to the Scene view overlay at the top
4. In the Scene view overlay at the top, press the "Cameras" button and select "Control the selected camera in first person."
5. Press anywhere else in the Editor and then press on the "Cameras" button in the top Scene view overlay again
6. Observe the opened "Cameras" window

Expected result: Size of the window is not broken
Actual result: Size of the window is broken

Reproducible with: 6000.0.52f1, 6000.1.9f1, 6000.2.0b7, 6000.3.0a1
Couldn’t test with: 2021.3.53f1, 2022.3.64f1 - “Overlay Menu“ selection is not present in the Scene tool overlay

Reproducible on: macOS Sequoia 15.5 (M3 Pro), Windows 10 (22H2)
Not reproducible on: No other environments tested