The syntax for setting time and duration does not work when editing a task
Using the advanced syntax listed here http://support.weekplan.net/topics/1789-how-to-add-new-task/
Editing a task and using this syntax causes no changes to the task.
There also appear to be some bugs with the syntax when adding a task, for example "Work out 9am ~2h" does not schedule the task for 9am-11am, it simply sets the duration to 2h.
When scheduling tasks I cannot select some times on the time picker. For example I cannot select 9am. When I move my mouse 1px the time jumps between 8:55 and 9:05. Perhaps consider using a material-ui style timepicker similar to this one http://www.material-ui.com/#/components/time-picker
Edit: I have tried the app on Android and the timepicker is just as bad there. It is nearly impossible to select the time you want using the slider.