re-docking puppet and properties windows while rigging

Hi. I have a dumb question. I somehow undocked the windows for the puppet and properties while doing rigging. I would love to get them re-docked into place instead of floating randomly, but the only option available in the menu is "close panel." Undock panel is there (although I want to re-dock it), but it is greyed out. I apologize for my ignorance.. Thanks in advance for your help.