I have a rattle in the windshield defrost vent. I want to remove the grill and add a little felt in hopes of stopping this pesky little rattle that echos throughout my vents like a ventriloquist.

I can squeeze the grill in the middle and it pops up but there is somthing on both sides (left and right) that is holding it in place and I just can't seem to figure it out.

Anyone know how to remove this vent grill?