The command option that is available with the Button widget and a few other widgets is a function that can make the programming of a click-of-a-button event easy. Many other widgets do not provide an equivalent command binding option.

By default, the command button binds to the left-click and the spacebar. It does not bind to the Return key. Therefore, if you bind a button by using the command function, it will react to the space bar and not the Return key. This is counter-intuitive for many users. What's worse is that you cannot change the binding of the command function easily. The moral is that command binding, though a very handy tool, is not flexible enough when it comes to deciding your own bindings.

This brings us to the next method for handling events.