Hi lithgowrailwaywo,

I can confirm that currently the ability to tab to switch to the Description within the Weekly Timesheets feature (accessed by +New , then Weekly Timesheet) is working when we ran a test. What may be occurring is potential browser interference which may not be responding to your ability to switch between fields by pressing Tab. What I would suggest is to follow the steps here to clear the cache and cookies on your web browser, before trying again. 

Thanks and let me know how you go, 

-Steven