One of the new component selection features in AutoCAD is the ability to pick components by a "lasso" that allows the user to choose the boundary of selected objects by moving their mouse, as if they were drawing the boundary with a pencil.  It kind of looks like this:

Unfortunately this ability can also confuse new and old users who are used to the old "box" type boundary selection that has been in AutoCAD from the beginning.  Here's some tips on how to control this new selection feature.

Delay the lasso time threshold environment variable:

1. Type in the following in AutoCAD:  (setenv "LassoTimeThreshold" "1500")  

2. Make sure you typed in the parentheses around that string as well.  What this does is that it gives you 1.5 seconds of "holding down your mouse" before the "lasso" selection tool kicks in.  By default, the value is set at 100ms, or 0.1 seconds of holding down your mouse.

Remove the lasso pick selection entirely:

1. Type the following in AutoCAD: PICKAUTO <enter> 2 <enter>

2. Where <enter> is the key command on your keyboard.  This restores the default functionality of the selection box to earlier versions of AutoCAD.  Make note that you can form a point to point fence with PICKAUTO set at 2 by pressing the "F" key while you are making a box.  

3. Additionally, you can access this variable by going to options > Selection tab > Selection Modes > Uncheck "Allow press and drag for lasso".