Zen mode activation
Double click on the top left corner of the notecard.
All notecards get collapsed and only titles are visible.
Zen mode deactivation
Double click on the top left corner of the notecard.
All notecards get expanded and visible including their contents.
Select notecards
Single click on the top left corner of the notecard to expand/collapse one notecard and see it’s content.
This is possible only when Zen mode is activated: