Crop problem

[vittumitäpaskaa]

Hi.
I am ahving a hard time while trying to crop picture.
if i just open the picture and start using polygonal lasso tool (without zooming picture) everything will be fine.
BUT if i want more quality on my cropping, ill zoom in and start clicking among picture.
Suddenly screen will flash after a "while" and all my hard work goes to trashcan.
It for some reason stops making line and simply decides to pull a line to beginning, right from where i started. In middle of work.
So frustrating that i can spend minutes to get smooth lines and BAM it goes right at beginning.
I am 100% sure that i wont doubleklick or do anything else stupid either.

And do we have some better way while moving close to object and we need to move picture?
I mean now when i am cropping and screen ends, i have to move over the screen to get more picture shown, it moves so frikking fast.
Can i somehow keep myself in centre on picture all the time while cropping?
Ty.

[vittumitäpaskaa]

wow, 3rd word and typed. and no edit. I feel myself like a pro.

[vittumitäpaskaa]

imageshack.us/clip/my-videos/189/owk.mp4/
Video to make it easier understand what i mean.