Some plans are not showing in overview screen

[f4ww4z]

When adding a new plan to a date that has many existing plans (2 is enough to trigger this issue), sometimes all 3 plans show up, other times it's just plans of the same type is showing.

This could be to do with each PlanItem's View not having a unique id. Right now, the id is set incrementally for each date, the top plan item View (in 1 date) having a base id and the next set of plans having just currentId + 1 as its id. We need to change the id so that it is unique for every plan View, no matter the date.