I intended to select objects with "Selection group" tool, so in order to achieve that:
pressed B hotkey with Alt or Ctrl or Shift button;
moved mouse to form rectangular area.
As a result it removed everything what was outside of rectangular area, forming infinite rectangular pyramid with it's tip on the position of my viewport when I was looking from when making selection. I can rotate around that pyramid now, where only objects (their parts) fitting that rectangular area are visible.
How can I cancel it to see all my objects back? Esc doesn't work.