Webkit - svg antialiasing issue when an <input> tag is present before the image

An SVG image is normally rendered by any browser with antialiasing. In Webkit, this is the case only when no <input> tag are present before the svg in the web app html file.

To reproduce the problem, open the QT Designer Wizard and create an HTML5 app. Then add an svg image in the index.html file.

Example:
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
<circle cx="100" cy="50" r="40" stroke="black" stroke-width="2" fill="red"/>
</svg>

When running the application, the circle is rendered with antialiasing.

Now, add an <input> tag BEFORE the svg.

Example:
<input type="text" value="Input text field" style="font-size: 20px; margin: 10px"></input>

The svg image in not more rendered with antialiasing...

What is strange is that if we put the <input> tag after the svg, there is no antialiasing issue...