Need help in autocad?

Trouble, when POST drew a new line in existing pulling.I was unable to see plus select this.
I attempted again upon it after changing large from blue to red-colored and very same result emerged.
But after i changed this layer and drew a new line then I can see and select that.
Why It happened Please a single give us ans.Involving it

Check On/Off along with Freeze
On / Off is employed to collection the coating will appear (on) or not (off) display monitor.Freeze is employed to frost nova a part.Which have been frozen coating means this layer is definately not included in subsequent functions.

Check in case current layer is UPON and Thaw (not frozen).