Modal's contents flashes on top of body before it's rendered

[atte-backman]

As the title says. The same behavior can be seen on demo-page as well.

[cynrichuysAE]

Duplicate of #5183?

[maxm450]

👍

[icfantv]

@cynrichuysAE, indeed it is a duplicate. @atte-backman, please extend us the courtesy of searching both open and closed issues before entering a new one. Processing user-entered issues is usually a time-consuming and cumbersome process (albeit, not in this case, as this was a quick resolution) so we ask that you please respect our time by doing some sort of due diligence first. Thanks.