Once a timer starts, the client and project it's assigned to can't be changed. I regularly start a time planning to tackle one project and then as I'm navigating to that project, see an unread email or coworker question that needs addressing. I should be able to change the client & project as soon as I change course. Right now, I have to wait until I've stopped the timer and then find the time entry on a report and edit it after the fact.