Issues with returning to edit mode.

Steps:
1. Create a new Landing Page with 2 zones.
2. Add Contentlist block to the 1 zone and Embed block to the 2 zone.
3. Complete configuration for Contentlist block (Limit 3, Types Place, Parent Places).
4. Complete configuration for Embed block (Content Paris banner).
5. Publish.
6. Return to edit mode.
7. Select Embed block
Result: Block is selected, action menu is displayed [OK]
8. Select Contentlist block.
Result: Block is not selected, action menu is not displayed, preview is not displayed.

Remarks: Please see attached.
The behaviour of the application after step 6 is not always the same. Sometimes it hangs on the spinning wheel. On one occasion Contentlist block preview was loaded and Embed block preview wasn't.