I've just had a quick look at the code and it looks like the bit that detects which browsers can use WYSIWYG is in includes/functions_editor.php starting line 165 (vb3.8.11 files)
Code:
if ($choice == 2) // attempting to use WYSIWYG, check that we really can
{
if (!is_browser('opera') OR is_browser('opera', '9.0'))
{
// Check Mozilla Browsers
if (is_browser('firebird', '0.6.1') OR is_browser('camino', '0.9') OR (is_browser('mozilla', '20030312') AND !is_browser('firebird') AND !is_browser('camino')))
{
return 2;
}
else if (is_browser('ie', '5.5') AND !is_browser('mac'))
{
return 2;
}
else if (false AND is_browser('opera', '9.0'))
{
return 2;
}
else
{
return 1;
}
}
else
{
// browser is incompatible - return standard toolbar
return 1;
}
}
else
{
// return standard or no toolbar
return $choice;
}
On line 180 I tested changing "return 1;" to "return 2;" this allowed Chrome (and I would assume all other browsers) to use WYSIWYG mode, however, I didn't check anything other than basic functionality so couldn't say how compatible Chrome is in that mode.