No New Tabs Appear!

I open up Unity and only the Game tab Appears! I’ve opened them up in a new window, but I can’t add them to the main window.

I figured it out, drag&drop didn’t work, but space bar did!

I’m not sure what’s your exact problem, but you can drag&drop any window-tab to any window by grabbing the tab-header and not the window header.

Next to the tab there is a little icon. Click on it and untick “maximise on play”.