I should add something for comparison.
100 SAZ in Fiddler Classic: memory usage is 75 MB
100 SAZ in Fiddler Everywhere: memory usage is 2,343 MB
I know they are completely different products, but I think this is related to the sluggish issue with too many SAZ.
I can confirm that indeed at this very moment, Fiddler Everywhere will load (as opened tabs) all entries in the Sessions list, which causes the performance issue you are observing. We are currently working on improved behavior where only the explicitly opened entries will be loaded as tabs, and you could expect that fix to be published with the upcoming 2.2.0 release.
Apart from that, the option to close multiple tabs simultaneously is a legit feature request - I am logging this one as a feature request and will present it to the team for future planning. Once again, thank you for your report and feedback!
Thank you so much.
Another suggestion: multi-selection of sessions capture. Currently you can only select one at a time.
It would be great to be able to select multiple ones using Ctrl or Shift.
I made the mistake to load a large number of SAZ files. They are not very big but it's a lot of them (about 100).
In Fiddler Classic, they just get appended together in the main Web Sessions list without any issue. However in FE, they are each their own entity. This seems to create considerable strain and the product behaves weirdly, throwing errors and being really slow.
It also does not seem possible to select more than one session at a time to delete them all at once.