I have several drawings open and at the beginning the left button single click and drag would draw the blue or green box to specify which entities to select. Now when I single click the left mouse button the command windows states "MainSelect Outside drawing boundary" without drawing the box. If i right click or esc the box will appear. This only happens on some drawings not all. If I hit the select entities button it will work properly and draw the box on the first left click. but after that it goes back to not working right. I am not sure what I have done but the auto select option is checked in the options>Drafting options>entity selection>Selection settings. Does anyone know why this is happening?

Thanks

EDIT: I found the issue. In Drawing Settings>Behavior>Drawing Boundaries> Enable Drawing Boundaries was not selected on the file that didn't have this issue. It was selected in all the files that did show this behavior. I deselected enable drawing boundaries and the single left click and drag box appears the first time. Now I understand what that option is for and how to use it when needed. 

Thanks.