hi Everyone

when i making polyline object

i pick every corner point and i connect tow or three lines ofter that it is disappearing showing polar traking cursor 

then i cannot finish the object.

when i making rectangle

i pick one corner the i go to another corner accidently i move my cursor to corner of some object my cursor automatically take the snap 

then i cannot finish my rectangle

sometime i pick both corners but i cannot see the object then i can see in print preview only i also showing cross lines

if anybody know please help me

thank you.....