- browser: > Microsoft Edge summary: > Implement the [`:dir()` pseudo-class](https://developer.mozilla.org/en-US/docs/Web/CSS/:dir) from Selectors Level 4 upstream_bug: > UserVoice#12299532 origin: > Bootstrap#19984 - browser: > Microsoft Edge summary: > Implement [sticky positioning](http://html5please.com/#position:sticky) from CSS Positioned Layout Level 3 upstream_bug: > UserVoice#6263621 origin: > Bootstrap#17021 - browser: > Microsoft Edge summary: > Implement the HTML5 [`` element](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog) upstream_bug: > UserVoice#6508895 origin: > Bootstrap#20175 - browser: > Firefox summary: > Fire a [`transitioncancel` event](https://developer.mozilla.org/en-US/docs/Web/Events/transitioncancel) when a CSS transition is canceled upstream_bug: > Mozilla#1264125 origin: > Mozilla#1182856 - browser: > Firefox summary: > Implement the [`of ` clause](https://caniuse.com/#feat=css-nth-child-of) of the `:nth-child()` pseudo-class upstream_bug: > Mozilla#854148 origin: > Bootstrap#20143 - browser: > Firefox summary: > Implement the HTML5 [`` element](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog) upstream_bug: > Mozilla#840640 origin: > Bootstrap#20175 - browser: > Chrome summary: > Implement the [`of ` clause](https://caniuse.com/#feat=css-nth-child-of) of the `:nth-child()` pseudo-class upstream_bug: > Chromium#304163 origin: > Bootstrap#20143 - browser: > Chrome summary: > Implement the [`:dir()` pseudo-class](https://developer.mozilla.org/en-US/docs/Web/CSS/:dir) from Selectors Level 4 upstream_bug: > Chromium#576815 origin: > Bootstrap#19984 - browser: > Chrome summary: > Implement [sticky positioning](http://html5please.com/#position:sticky) from CSS Positioned Layout Level 3 upstream_bug: > Chromium#231752 origin: > Bootstrap#17021 - browser: > Safari summary: > Implement the [`:dir()` pseudo-class](https://developer.mozilla.org/en-US/docs/Web/CSS/:dir) from Selectors Level 4 upstream_bug: > WebKit#64861 origin: > Bootstrap#19984 - browser: > Safari summary: > Implement the HTML5 [`` element](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog) upstream_bug: > WebKit#84635 origin: > Bootstrap#20175