Some flickering occurs when having IMGUIContainers in the scrollview. This is likely caused by the fact that now the layout of scrollview is performed in multiple frames (see [https://fogbugz.unity3d.com/f/cases/1417765)|https://fogbugz.unity3d.com/f/cases/1417765).] and [https://ono.unity3d.com/unity/unity/pull-request/144736/_/uitools/fix-1417765).]

Steps:

1 - Create a document

2 - Select the Root item in the Hierarchy pane

3 - Resize the UI Builder window to squeeze the inspector to a really small height to display the Scrollbars

4 - Enlarge the UI Builder window bit by bit a couple of times

Actual outcome:

The flickering happens