"if I put the cntl down while still holding the cmd and mousebutton, the event changes
  to mouseMove CMD CNTL blue and moving the mouse moves the Browser window."


You want, as revealed by HandMorph showEvents: true:


mouseMov Ctrl blue


What you have, above, is too much. Remove the "CMD" and you should have it.

See here:

http://www.smalltalktelevision.com/mouse2.mov


Chris