* elements which possibly depended on this depend now on `visibility` of element added
* changed everywhere returns on addWidget
* checked layouts (vertical, horizontal, pagedbox, gridlayout)
First asign size -> than addWidget to parent
Element created should have first assigned it properties, then there
should be try to add to parent widget - othervise parent widget tries to
position elements based on default values.
This design is generally silly at most as if we fail we cant just delete
the child, we cant react properly. We could throw and hope that someone
will try to catch it - but if they do, they should be able to first
create item, than try to add it to parent in the first place.
