Firefox tries to save a page with a defaul .com file extension but should be .htm or .html

Firefox insists on saving a page using a .com extension (from the web name) In a Windows environment a file that ends in .com is considered an executable, and it is the wrong file extension to use. When I save a page I expect Firefox to be smart enough to know that a web page name should have either an .htm or .html file extension. Every time that I save a page, I need to manually modify the file extension because the default is .com