If the hinge clips are not snapping in place or they do not stay attached, it could be that one of the tabs are missing or damaged on either the hinge clips themselves or on the LCD assembly. 

The pics below show where to check the condition of these tabs. Also, in the hinge clip pics, you can see how to distinguish between a left and right hinge clip by checking the text found in the middle of the clip. Yes the text is microscopic but it is an option. Left will show an "L" and the right will show an "R" within "SM#2R1"

Hinge Clips

The LCD assembly