weighting problem

hi

i have this mouse model, but in this particular bone as seeing in picture, the vertices act loudly when i assign to them weight (even if it is the lowest wieght possible to assign).

here is the model and armature, in the red circle is a vertice that dont have any weight at all.



in here i rotate the bone. vertice in circle doesnt move.


but in here, when i assign very very low weight, the vertice moves as if i assigned 0.7 weight to it.


what is wrong? i want the bone in the picture to have a very minor effect on the vertice.
how to do it?

here is the blende file
XFCE_mouse_22 a backup.blend (1.01 MB)

Vertex weighting determines the influence between multiple bones. That vertex is only influenced by that one bone and follows only that bone if any weight is set on it. No other bone is influencing it to hold it back. If you paint some weight on it for the spine bone too then the weighting comes into play and will determine how much influence either bone has on that vertex.

-LP

right. thanks