The ability to specify the pixel height of the Web Content iFrame has gone missing. There's a drop down now, however, it only offers a few choices, and they are not useful for all circumstances, hence you need to be able to specify it mannually.
Some examples are having a very short window with an important message you want to stick on the top of the page, such as using a Web Content tool to display a warning about how to interpret a specific grade; you don't want to force it to occupying 300 pixels. You might also have a very long Web Content tool, for which 2400, the max, is not sufficient.
A combo box with drop downs or manually type in would be okay.