Can't edit timeslip dates!

I entered a timeslip yesterday for a project I worked on Saturday, but I didn't check the date and it was added to Sunday. I found there was no way of simply "changing" the date, I had to delete the entry and create a new one.

There should be an option to edit the date of a timeslip.

Also, could we have a notes field which isn't visible to the client? I'd love to track internal notes without having them shown on invoices.