Right now the Timeline shows all edits by both users on pages where both users have made 1+ edit, regardless of the edit date. Given that Wikipedia is 17+ years old, there are a lot of "two ships passing in the night" edits that may take up space on the Timeline, especially on popular pages (e.g. Village Pump) — see also {T189850}
If two users edit the same page over a long period of time, they are not interacting. ([[https://tools.wmflabs.org/sigma/editorinteract.py?users=Fox&users=The+Interior&users=&startdate=&enddate=&ns=&server=enwiki|Like these two users on the Iguana article.]]) I'm calling this the "interaction threshold"[1] — for now it is set to 'all time' but this is turning out to be too simplistic. Because 'all time' already exists and hypothetically could serve a purpose we should keep it as a somewhat hidden option — for work in a later task: {T190208}.
If two users edit the same page over a long period of time, they are not interacting. ([[https://tools.wmflabs.org/sigma/editorinteract.py?users=Fox&users=The+Interior&users=&startdate=&enddate=&ns=&server=enwiki|Like these two users on the Iguana article.]]) I'm calling this the "interaction threshold"[1] — for now it is set to 'all time' but this is turning out to be too simplistic.
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====Acceptance criteria
* Whatever is set within the date range parameters should define the "pages where both users have edited"
[1] Shoot me if I ever suggest putting the words "interaction threshold" in the UI. ☠️
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====Future related task
* Because 'all time' already exists and hypothetically could serve a purpose we should keep it as a somewhat hidden option — for work in a later task: {T190208}
* {T189850}