This is by far the shortest Forum Leaders tips I will likely ever post because I described it all in the title! 
Try it out!
PS: setting the duration back to a number greater than 1 will unmark it as a milestone!
See all of my top tips & tricks on my website.
Surprising but great!
Short but efficient! 
I’ll add that if you want a task to be only on a single date and enter a “0” Duration but don’t want it to be a milestone, you can manually unmark it as a milestone after Asana converts it to be one.
But, @Phil_Seeman , in that case, wouldn’t you just enter 1 instead of 0?
Yes, you’re right, you would normally do that. I guess my point was that I thought it was good that one could still manually mark/unmark a milestone regardless of what was put into the Duration; I wasn’t sure that would be the case so tested it to confirm.
This sounds like a great new design pattern to use widely:
Just use 1s and 0s to indicate whatever you want. Perfect for engineers!
In this case, 1 is Task, and 0 is Milestone.
To expand a group, hover and type 1, to collapse, type 0.
I really like specifying Approval tasks with the easy-to-use -1!
(I’m just making bad interaction design jokes and teasing here, not casting aspersions on Asana’s design, which is world-class.)
Thanks,
Larry
It definitely becomes a milestone.
It remains a milestone even when moved to a list.
That’s an interesting way to use the period in the Gantt view.
I’d also like to see improvements to the Gantt view itself.
A post was merged into an existing topic: Allow Start Date for Milestones