We just pushed a Basecamp update that includes a long top-requested feature: A calendar date picker for milestones.
Now when you add a new milestone, or edit an existing milestone, you pick the date from a calendar instead of a series of pulldown menus.
Today's date is in light yellow for reference. The date you select is highlighted in black and repeated at the bottom of the calendar. You can move through the calendar quickly using the back/forward arrows or jump to any month/year up to 3 years in advance with a single pulldown menu.
We hope you find the calendar date picker useful. We're really happy with it. Thanks for your continued support.