[Bug] TwoGrids sample in DWC does not render second grid when running inside GUI embedded BBjHtmlView (Chromium)

[StephanWald]

Describe the bug
The second grid in the two grids demo only renders upon first refresh whe running as DWC inside BBjHtmlView in GUI.

To Reproduce
Steps to reproduce the behavior:

1. Deploy TwoGrid.bbj as DWC
2. Fetch the sample code from https://documentation.basis.cloud/BASISHelp/WebHelp/bbjobjects/Window/bbjhtmlview/bbjhtmlview.htm and change the URL to point to the localhost DWC TwoGrids.bbj sample
3. run in GUI and observe that the second grid does not render

BBj 24.20 / GridEx 1.17.0

[StephanWald]

Testing revealed that commenting out Line 1341 in BBjGridExWidget is #getExecutor().flush() fixes the issue, so it might be a race condition.

BBjGridExWidget/BBjGridExWidget.bbj

Line 1341 in 846d40c

#getExecutor().flush()