The dialer app uses a variety of different overlay/dialog implementations to display various messages, these include: - The non-element confirm dialog available under shared/ (shared/js/confirm.js, shared/css/confirm.css) - The custom dialog available under shared/ (shared/js/custom_dialog.js) - The "loading-overlay" node (https://github.com/mozilla-b2g/gaia/blob/fb0f486244b68fd63c5dee993c1811f41e787a74/apps/communications/dialer/index.html#L284) which is implemented ad hoc in apps/communications/dialer/js/mmi_ui.js and uses the styles in shared/style/animations.css We should replace all of them via the gaia_confirm shared element, possibly improving it to support a progress bar as currently used by the MMI code.

As a side note, possibly due to the CSS shared classes sometimes when showing/hiding a dialog you can catch a glimpse of another one. I've seen it happen only a few times and it's visible only for a fraction of a second so it's impossible to tell which one is it.