The Xerox system required you to select a command in order to do anything, ranging from resizing a window to changing the extension that located a file.
The issue is an Adobe software called Flash, which does many things, most notably letting Web surfers view streaming video inside a browser window. (As opposed to downloading the file and then playing it with something like Windows Media Player.) For a long time, this was the easiest way for Web sites to deliver video, and Flash has been almost universally adopted.