height= in CSS?

I was trying to get dhtmlxLayout to work. It works OK, but I get a lot of errors concerning the CSS-file. One particularly made me frown, namely:

    height: 16px;


If I’m correct, the CSS-rules state that’s illegal, so what is the use?

It is ignored by the modern browsers, but will be accepted by IE6 ( which have different sizing logic )

Well, it makes sense. But wouldn’t it make more sense to include statements as that only if the browser is IE6?