I just want the equivalent of closing and reopening my main program. I want to invoke it when a "new"-like option from a drop-down menu is clicked on. Something like calling root.destroy() and then re-initiating the mainloop.
How can I get this done?
You could take all your GUI building logic and initial state code out of the mainloop and put it into functions. Call these functions from the mainloop (something like: buildgui() & initstate()) and then, when the user clicks your menu icon, just call initstate() to set it back like it was when the application first started.
Resetting the main GUI window