Dynamic Atlas Viewer does not display an atlas when UI Toolkit Debugger window is closed and reopened again

Steps to reproduce:

1. Create a new Unity project
2. Open UI Toolkit Debugger (Window > UI Toolkit > Debugger)
3. Click on the "Select a panel" dropdown and select "Toolbar"
4. Click the "Texture Atlas Viewer" button in the UI Toolkit Debugger window
5. Close the UI Toolkit Debugger
6. Repeat steps 2, 4, 4
7. Observe the Dynamic Atlas Viewer window

Actual results: "No atlas to display" message is shown

Expected results: Atlas from the "Toolbar" panel is shown

Reproducible with versions: 6000.0.43f1, 6000.1.0b11, 6000.2.0a7

Tested on (OS): MacOS Silicon Sequoia 15.3