See this
http://www.macromedia.com/cfusion/knowledgebase/index.cfm?event=view&id=KC.tn_18
893&extid=tn_18893&dialogID=25158270&iterationID=1&sessionID=9630db4fd22d6624473
7&stateID=0+0+25162866&mode=simple on the Macromedia, sorry Adobe tech support.
It list various issues with Freehand and Moc OSX 10.4, including the snap to
grids. This was posted last year but seems that nothing is gonna be done about
it. I was having the same problems recently and there are ways around it e.g.
set your snap to grid settings to 0.00001 (defaults to 0) to 'deselect' it.
Check out other similar postings on this forum...