Thanks Paresh. This worked for hiding the All Timesheets of other users, however, when I now log on from a Timesheet Manager account, I cannot see the timesheets of other users.

I fixed this by going to the Timesheets Users group and removed the account from there, and made sure that the user account is ONLY in the Timesheets Manager group. I wonder why Odoo did not perform this task when the account specified Manager?

Anyway, thanks a lot for your help.

Paresh, I'm trying to understand the Apply for Read Access Rights that I applied and the logic doesn't seem to make sense. The suggestion that you made works! but I'm just trying to understand why enabling Apply for Read caused this behaviour. It seems like Apply for Read should allow for users to read their own timesheets, but it was unchecked before and you could see all users timesheets. Why did applying this disable that? it seems backwards.

"Apply for <operation>" means the condition specified in the record rule should be applied when that particular "operation" is performed on the model. Since the "Apply for Read" checkbox was disabled in the default setting, the record rule was not being applied on "Read" operations on the model which was causing all timesheets to be visible. Enabling it, makes Odoo apply the condition specified in the record rule on Read operations on the model.

Timesheet Manager has all the rights of the Timesheet User plus more. That's why when you add someone to the manager group they are automatically added to the user group. Do you have no an example of what you are trying to do?

Odoo uses a layered mechanism for managing security. For example, in the case of timesheets, the Timesheet User group is assigned the basic rights to do timesheet entry. The Timesheet Manager inherits these rights (take a look at the "Inherited" tab in the Timesheet Manager security group) and provides more rights in addition to the ones provided by the Timesheet User group. All the security groups in Odoo are assigned this way.

Hope this helps.