Mysterious tkinter bug: tk.Button doesn't think it passed event <1>

[Ben Elam]

On Thursday, July 2, 2015 at 5:34:19 PM UTC-5, Ben Elam wrote:
> I've stripped things down to the least amount of code necessary to reproduce the error. I can make tk.Button handle event '<3>' but not event '<1>'. That is, the function the event is passed to receives the event and can even print the address of the event object, but a callback later produces an error suggesting that no event was actually passed to the function. Also, tk.Label handles '<1>' without problem. What gives?
> 
> Code, errors, and slightly more details here:
> 
> http://ingcake.github.io/2015/07/02/tkinter-feature-request---clickable-button/
> 
> I hope I'm just doing something dumb; any help would be much appreciated.

Pulled the original post because dumb.
For posterity, here is a gist with the original code, along with the original error messages:
https://gist.github.com/ingcake/aa4e01687dd81890c8fd