PropertyGrid
When an editor is opened and a property grid is displayed in a modal window:

Users can click on the list arrow to show the list as above...
The drop down of the property grid appears. When users hit Esc key, it will be cancelled (expected) and list disappears. But from this point onward clicking on the button will not work properly anymore. It seems that the ScintillaNET does not let the top modal window to process all the users integration (messages).

By clicking on the list, it gets the focus but does not show it anymore. Randomly works, or with delay. I understand this is a very strange issue.
Where and how do I start tracking and tracing this?
If that helps... by changing Editor.IdleStyling from AfterVisible to ToVisible the issue goes away.
Any thoughts?