Webpage :https://developer.microsoft.com/en-us/microsoft-edge/testdrive/demos/fishietank/
There are two issues
1) Popup dialogue is not visible in qt browser whereas it is visible in desktop linux qt browser or any other browser.
2) page is displayed at top left corner with small size
Issue is reproduced with weston, X11, compositors and eglfs

Findings: After debugging with remote insector,
Issue #1 : dialogue is visible when removed margin property of div
issue#2: webpage is displaced with proper scale when ", initial-scale=1.0" is added in meta tag with viewport.