[Jeff]

If you're going to use the viz.callback command to handle button events then you should set it up with one callback function. Another way to do this is using vizact.onbuttondown and vizact.onbuttonup. In this case, you should create separate callback functions for each button event:

import vizact

def n11ButtonDown():
	print 'n11'
	
def z11ButtonDown():
	print 'z11'
	
def z12ButtonDown():
	print 'z12'
	
vizact.onbuttondown(n_checkbox,n11ButtonDown)
vizact.onbuttondown(z_checkbox_p,z11ButtonDown)
vizact.onbuttondown(z_checkbox_n,z12ButtonDown)