Screen works but testing it before gluing it down makes it black

I got the screen replaced and it works. I have not glued down the screen yet. When the phone is booted up and I press down on the screen (as it would be if it were glued), it looks mostly black. I did remove several layer of material from the back of the LCD that came shipped on it, like a reflective mirror piece and a clear piece. Anyone got any ideas? The backlight is working for sure on the LCD at the top. I just don’t want to glue it down and then have to remove it again.