Python3 Tkinter popup menu not closing automatically when clicking elsewhere
Try calling the method tk_popup rather than post.
Also, your code has a memory leak, in that each time you right-click you're creating a new menu but never destroying the old one. You only ever need to create one, and the reconfigure it before popping it up.
To close the popup menu when click elsewhere, you can add
rcmenu.bind("<FocusOut>",popupFocusOut)and call unpost in popupFocusOut.
def popupFocusOut(self,event=None): rcmenu.unpost()