Visualforce Page on Page Layout in Lightning Community

The Problem

By default Visualforce page doesn't work on page layout in Lightning Communities. It renders, but no interactions are possible because of a link tag

<a class="mask" title="<Visualforce_Page_Name>" href="javascript:void(0);">
   <span class="assistiveText">Expand</span>
</a>

Inline page behaves like a link, and when you try to interact with a page, it opens a new tab with wrong page URL /<portal>/s/<portal>/<Visualforce_Page_Name> saying "Invalid Page". Where - your community name.

The Solution

Go to Community Builder => Theme => Edit CSS

Add the following css:

.oneAlohaPage .mask {
    display: none;
}