Thank you, this solved the problem in fact, but only partially. This is the screen view I get in Bitrix https://goo.gl/dznQbp, I can share only 1 screen, but it still does not allow to maximize the window and the shared screen is unreadable and of low resolution. The view should allow full-screen mode like Skype does https://goo.gl/9iiXBo.
Another problem is that when I pick one of the screens to share, the other one automatically turns off - also for me as the screen sharer. I very often multitask, so I need to share one screen during the call and simultaneously work on the other one not showing its view to chat participants.
Can I create a post on a particular group's wall which will be repeated (weekly, monthly, quarterly, yearly)? Actually it's goal is to remind my team about the performance reports - should it be a post, or there's a better solution to it?