Incorrect arrow appearance with Firefox
Choose "Menu" > "Custom Arrows" and use custom arrow code (Unicode arrows) for your menu:
s1064.zip sample project
The problem is caused by incorrect DTD processing by Mozilla browser engine. If your HTML code begins with
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
remove entire DTD declaration ("http://www.w3.org/TR/html4/loose.dtd") from your HTML page, modify the line to:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">