Text:html in simple vertical scroll won't centre properly

I find I can only get my vertically scrolling text to centre properly by placing a full line of blanks somewhere in the text.(I’m putting them in the first line.) Similar problems arise with right-aligned text. I guess lots of people would want vertically scrolling titles, so nice of this could be fixed.

Here’s the html that follows the javascript in the “simple_scroll.html” file that Shotcut produced. My dummy line of spaces is included. I’ve played about pasting this into an html file which I can then open with my browser. The centering behaves just like it does in Shotcut, both with and without my extra line (except it doesn’t scroll of course). So I deduce that the problem is in the html. Unfortunately my skill in html and css is not good enough to identify the exact problem.

 <style>
        body {
            position: absolute;
            margin: 0;
        }
    </style>
  </head>

  <body style="font-size: 72pt; white-space: nowrap;"><div style="text-align: center;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</div><div style="text-align: center;"><font face="Arial">This is a test</font></div><div style="text-align: center;"><br></div><div style="text-align: center;"><br></div></body></html>

The problem arose in a 1280x720 video.
I’m using Shotcut 19.10.20 under Windows 10 home v1903 build 18362.476 on a 3 Ghz Pentium G3220
with 4GB of RAM and a 1920x1080 display. Been using Shotcut happily for a year or two with very few issues, though haven’t been very adventurous in my use of filters.

Don’t know what happened to the html. Looks as if it has been stripped out.

See this thread.