If "active", this is a "default" button for the window, i.e. the one that will be invoked if
the user presses Return. Regular state is "normal" (You need to set up the event binding separately.)
image, compound
Specify a Tk Image object (not the path to an image file) instead of the text label.
If compound is center, top, bottom, left, or right, display the text and the image.
How do I...
Press the button from my program?
Use the "invoke" method. Useful so you don't need to repeat the button's command script
in multiple places in your program.
Disable the button?
Use the "state disabled" method. You can reenable this with "state !disabled".
Check with "instate disabled" (returns 1 if disabled, else 0).