I just created a sample listbox with drag & drop support and it indeed
looks better if the "hand2" cursor or whatever cursor is set only shows
up when motion starts. But, for the sample included with Tkdnd, I find
it better to show up the different cursor when clicking the canvas item
instead of waiting to starting move it.
Are you willing to adjust that ?

The first feature added -- to support custom cursor is fine, just this
second change needs to be rethought.