collapse.js default toggle accordion behavior

[lustremedia]

Suggestion:
Why is the default accordion behavior (open a single toggle and close all others) dependent on '.panel' class

Couldn't this be decoupled into a data-attribute?

e.g. data-toggle-option="single" (opens the clicked toggle, closes all others)
data-toggle-option="individual" (opens each toggle independently, leaves opened toggles open)

Source ref: https://github.com/twbs/bootstrap/blob/master/js/collapse.js#L43

[cvrebert]

Duplicate of #10966.
We hope to address this in Bootstrap v4.

[lustremedia]

Thanks for the heads up! Looking forward to v4.