Why not just do it yourself with global variables? Use this precise order of actions:
Always:
set mouse_dist to distance(mouseX, mouseY, global('old_x'), global('old_y')
set old_x to mouseX
set old_y to mouseY
'Mouse is moving' condition would be equivalent to mouse_dist different to 0, and 'On mouse moved' condition would be equivalent to mouse_dist different to 0 followed by 'Trigger once'.