I've tried, several times and unsuccessfully, to establish a sequence of steps for this issue to happen, but I was unable to do so. So please consider this issue or close it by "unable to reproduce"

Back to the issue:
Sometimes, when i'm working in several sequence tasks that implies the appearance of notifications, a blank space is left on the top when the notification disappears.

In the attached image1, one space was left by one notifications. After working a bit more with eZ Platform, a second space appeared again after a notification disappeared (image2).

If I refresh the page (Ctrl+F5), then all is back to normal