Allow user to type in the interval time instead of just clicking the up and down arrows

[navinthomas]

Clicking the arrows to increase the timer to something like 50 mins from 25 mins requires 25 clicks of the up arrow. It would require the same number of clicks of the down arrow to go back down to 25 mins. This is not a great experience for users who want to switch their interval times frequently depending on the kind of work they do.

It would be better if the user could also place the cursor in the number area and type in the number of minutes that they want. So the user can use the arrows for small changes in the interval time, but can type for bigger changes in the interval time.