drag event when sprite scaled

[scofieldly]

hi everyone,

Here is the problem I meet,
 

I have a sprite and I can drag it in the right way when game has normal scale

but when I  change scale by 
game.world.scale.setTo(2);
things become different.

 

the sprite moving distance become twice as my cursor moving distance, when the scale becomes 3 the distance also become triple as well. 

 

so do you gays have any good ideas for sync cursor and sprite position, many thx.