OK, I think this will do the trick...in the extension setting set the following key to Custom and either blank or false.

Gotcha, we have that issue registered and I hope to get something in place in Q1 2023 to improve that experience.

Thanks for the clarification, are you working with a Virtual Desktop environment where a particular user could be on any number of devices?

Since we don't offer the option to multi-select and join, we would not do this. The items that are greyed out indicate that it is not possible to do against more than one machine simultaneously. 

Most likely one of the timeout settings need to be adjusted:
Advanced Configuration Editor - ConnectWise

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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)

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