I'm editing a card with a somewhat long description (I've done much longer). Both the browser (firefox) and Windows 10 app are going crazy.
Every character typed makes the view go up and down like that, and it becomes quite unusable.
Hey @xavigisbeg - do you mind raising this as a ticket over at Trello Support and sharing the URL of the board you're editing the description on? You can raise a bug ticket at https://trello.com/contact