Our introduction of lazy loading, as part of our recent redesign, was originally limited to just three columns: Backlog (for Scrum Boards), Done, and Trash.

We figured that these columns were most likely to be very long, and would therefore benefit the most from implementing lazy loading.

This worked well; so well, in fact, that we have expanded our use of lazy loading to work with all columns, across all Task Boards and Scrum Boards.

The practical effect of this should be to reduce the time needed by the browser to load large boards, for all users, on all kinds of computers.

Enjoy.