Steps to reproduce:
1. Create a Universal 2D project
2. Create any Sprite Asset (Create > 2D > Sprite)
3. Create two Sprite Library Assets (Create > 2D > Sprite Library Asset)
4. Select one of the Sprite Library Assets and select another Sprite Library Asset as Main Library in Inspector
5. Press “Open in Sprite Library Editor” button
6. Drag and drop Sprite Asset into Sprite Library Editor window
7. Select another Sprite Library Asset as Main Library in the Sprite Library Editor window
8. Select parent Sprite Library label press “Save” and “Yes” on pop-up windows to save changes
9. Open Sprite Library Editor window for child Sprite Library and observe

Actual results: Sprite Asset is no longer in child Sprite Library and “SerializedObject target has been destroyed.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)” error is thrown
Expected results: Sprite Asset is in child Sprite Library

Reproducible with versions: 9.2.1 (2022.3.65f1), 10.2.1 (6000.0.55f1), 11.0.0 (6000.1.15f1), 12.0.2 (6000.2.0b12), 13.0.0 (6000.3.0a4)
Couldn't reproduce with versions: 7.2.0 (2021.3.55f1) (No Sprite Library Editor window)

Tested on (OS): Windows 11, macOS Sequoia 15.4 (M4)