Sometimes when I open Libre Writer document it doesn't show its window.
But I can see from the launcher that in fact it is open.
When I opened multiple documents, the same behaviour - if I click on the Writer's launcher, invisible windows hover - only close buttons are seen.
The problem was solved after I deleted configuration files of libreoffice from /home/.config directory and entered through Libre Office from the Dash.
But, what caused the problem?