DisplacementMap Help

wonder i someone could help me

im trying to use a displacement map with a mask
(is it even possible to do?)

i have a magnifying glass thats using startDrag and the displacementMap is following it.
thats all working, but the minute i use “setMask” it breaks

attached is the file
appreciate any feedback
thanks

http://www.midnitefx.net/test.zip