Call for helps : Grease Pencil issue with shift

I use 2.8 beta, with the Grease pencil, it works very well, but suddenly It doesn’t work,

Every time I need to hold shift to draw, if not, even I am in (Draw Mode) with DrawPencil selected,
it still keeps as the Grab situation, Every time I need to hold shift, then I could use Grease Pencil Draw.

Is anyone know What happens with this problem, I spend two days to search it, no result at all…
it’s very kind if you could give me a hand, Thanks & my mail: