It's a joke they still haven't fixed the fullscreen feature rendering your second monitor useless. I can't understand why they did it that way and why it hasn't been fixed already.
Go full screen on any display
If you have a secondary display connected to your Mac, you can take an app full screen on either display. Drag the window to the desired display and click the full-screen button.
edit: You can drag child windows of the full-screened app to the second monitor. The whole point of the full-screen mode is to isolate the app and give it exclusive focus. For everything else, there's the zoom button.
Uh, no. You can't. That's the gripe. Way to be dismissive when you don't even grok the complaint.