When you share a dashboard with a user group, agents within the group can access it in a read-only mode, preventing them from changing anything.
But let's say you've set up a dashboard for agents to view their individual performance metrics. Then it could be helpful for them to change the time range to yesterday or current week instead of having it fixed to today only.
From now on, when dashboards are shared, agents will, by default, be able to tweak the time setting (but can't save it).
If you still want to lock down the selected time, you can change this from the dashboard settings.