Currently, only the first file in the selection is used to Open and Reveal actions. That's to avoid accidents with many files being selected.
It's useful in some cases to open/reveal more than one file at once, so a better approach would be to warn the user when there's too many files selected.
It would be nice to do that one in a near release.
(from [93eeeb2f0de9]) Allow "Open selected" to open more than one file at once.
When there's mpre than 10 selected dupes, a warning is shown, asking
confirmation. [#142 state:fixed]