Steps to reproduce:

1. Open the attached project
2. Switch to Web Platform (If it's not already set)
3. In the Module Stripping Window, select the Build
4. Press the Run button to start a standalone player
5. Close the Player
6. In the Module Stripping Window, press the Select Submodules (This may require setting the stripping settings assets if not already set)
7. Expand a few module sections in the list
8. Scroll up and down the list

Actual results: Scrolling is choppy and unresponsive. Depending on how many sections are expanded, list items may not be rendered for a split second after scrolling

Expected results: Scrolling is smooth and does not cause performance drops inside the Editor

Reproducible with versions: 6000.3.0a3, 6000.3.10f1, 6000.4.0b10, 6000.5.0a8

Not reproducible with versions: 6000.0.68f1, 6000.3.0a2

Tested on (OS): macOS 26.3

Notes:

• The issue was also reproduced with the Package Manager window when scrolling the available packages list. PM is also using UIToolkit
• The issue was not reproduced with Project Window, which is using UGUI