Description of problem:
When I am in the Evolution Mail window, the Search bar is conveniently above the Inbox preview. At times, I am searching for multiple messages based on subject.
As an example:
I have multiple alerts from Nagios, which have the subject line of the device with the fault. I would like to search for all entries for particular devices, not just one at a time. So I would like to be able to enter something like S001|S005|S007|S020 and have Search show the messages with the subjects that contain S001, S005, S007 and S020.
I noticed the "Free Form Expression" option but had not idea of how to use it.
Eventually I stumbled on:
It's brilliant option (Thank you Milan!), but please could we put some guidance on how to use it in the GUI somewhere?
Version-Release number of selected component (if applicable):
Thanks for a bug report. As this is not Fedora specific, it would be better to have that filled upstream, as a request for the user documentation . In fact, the user documentation contains the link you pasted above , I guess you found it there. I agree, it could have received more detailed instructions, ideally with examples, making it easy to use for the users.
As you used the past tense in "but had not idea of how to use it", I suppose you figured it out already.
I will file a bug on Gnome as you suggested.
Yes, I found the link  from a Google search, and that sorted me out.