This is not something we will be adding, the purpose of the timeline is simply for events related to ConnectWise Control session events.
(View a session timeline - ConnectWise)

We've got you covered!

Search for a session - ConnectWise

You can use a session filter for this something like:
FirstEventTime > $1DAYSAGO

any integer will be accepted ie: $7DAYSAGO

Thanks for the clarification, I understand the use case now. 

Jay,

Can you provide more information on exactly what you mean when you say 'Right now, it switches all open sessions to backstage when you go backstage on one session to a computer.'

I took this to mean if a technician had multiple session open from the same control instance on the same host computer, that if you switched one of the sessions to backstage, all of the sessions on the host computer would switch to backstage, however I am not able to duplicate this.

This can be accomplished using session group and session properties, I am including a couple of links that may be helpful, but if you have any problems, I recommend contacting our support team.

Create session subgroups - ConnectWise
Create session subgroups - ConnectWise