How to reproduce:
1. Open attached 'project-1174406.zip' project
2. Select all the sprites in 'Assets' folder
3. Drag the sprites into 'DragHere' gameObject in Hierarchy window
4. Select 'Cancel' in 'Create New Animation' pop-up window

Expected result: no exception is thrown
Actual result: 'InvalidOperationException: Stack empty.' exception is thrown

Reproducible with: 2019.2.0b4, 2019.2.1f1, 2019.3.0a1, 2019.3.0a9
Not reproducible with: 2017.4.31f1, 2018.4.6f1, 2019.1.14f1, 2019.2.0b3, 2019.3.0a10, 2019.3.0a11

Note: the sprites have to be dragged on to a GameObject in Hierarchy window, otherwise the exception is not thrown

Exception:
InvalidOperationException: Stack empty.
System.Collections.Stack.Peek () (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
UnityEngine.GUI.EndScrollView (System.Boolean handleScrollWheel) (at C:/buildslave/unity/build/Modules/IMGUI/GUI.cs:1481)
UnityEditor.IMGUI.Controls.TreeViewController.OnGUI (UnityEngine.Rect rect, System.Int32 keyboardControlID) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:605)