is mobile click delay really fixed through CSS?

[AndyOGo]

According to BS4 reboot:

Traditionally, browsers on touchscreen devices have a delay of approximately 300ms between the end of a “tap” – the moment when a finger/stylus is lifted from screen – and the click event being fired. This delay is necessary for these browsers to correctly handle “double-tap to zoom” gestures without prematurely triggering actions or links after the first “tap”, but it can make your site feel slightly sluggish and unresponsive.

Most mobile browsers automatically optimize away this 300ms delay for sites that use the width=device-width property as part of their responsive meta tag (as well as for sites that disable zooming, for instance with user-scalable=no, though this practice is strongly discouraged for accessibility and usability reasons). The biggest exceptions here are IE11 on Windows Phone 8.1, and iOS Safari (and any other iOS WebView-based browser) prior to iOS 9.3.

On touch-enabled laptop/desktop devices, IE11 and Microsoft Edge are currently the only browsers with “double-tap to zoom” functionality. As the responsive meta tag is ignored by all desktop browsers, using width=device-width will have no effect on the 300ms delay here.

To address this problem in IE11 and Microsoft Edge on desktop, as well as IE11 on Windows Phone 8.1, Bootstrap explicitly uses the touch-action:manipulation CSS property on all interactive elements (such as buttons and links). This property essentially disables double-tap functionality on those elements, eliminating the 300ms delay.

In the case of old iOS versions (prior to 9.3), the suggested approach is to use additional scripts such as FastClick to explicitly work around the delay.

For further details, see the compatibility table for suppressing 300ms delay for touchscreen interactions.

[LucaMele]

closing as new plib version is live. If issue is with v2 still relevant, please re-open