Not so much a solution as a workaround to at least make the white flash less annoying.
1. I found this suggestion here
In your style.css, create an entry for HTML.
Like this -
2. I tried several places within the Atahualpa file structure and finally found that if I took a portion of his suggestion (just the color) and put it in css.php, just before:
text-align: center; /*
I now get a flash that is the same color as the background on my toolbar, so it, while not fixing the problem, makes it less annoying; at least to me.
The actual snippet I put there was:
Hope it helps...