Weird web gui behavoiur

[Labsy]

Hi,

after upgrading to ZCS 7.0.1 I've been noticing - don't know exactly how to describe - something like "random unexpected WEB GUI jumps" in Firefox, like:
- Admin console was opened in one of TABS, then all of the sudden, when waiting to enter credentials, the "waiting" mouse pointer pops up, and admin gui opens up in a new window
- As User in webmail, just during typing view switches from compose new message window to Calendar or Briefcase tab
- When I am sure I left webmail opened in Mail tab, I return to computer after couple of minutes and I find it opened in Calendar or some other tab

First few weeks I was sure my computer in the office is acting weird, but last few days I notice the same weirdness also on my home computer.
When unexpectedly switched to Calnedar or other tab, there is no appointment waiting, nor any other alert, like some settings error or such.

Anybody else noticing such a behaviour?