I just assembled the Billy bookcase (15 3/4" width) and installed the Billy Ydre door. When viewing the floor model, I remember the door being flush with the cabinet when closed. However, after finishing assembly, I noticed that there is a gap where the knob side of the door meets the cabinet and the door does not fully close. Not sure what is causing this gap. Any tips? I have another set I have yet to assemble and would like to finish/correct the first before beginning the second. Thanks for any and all suggestions.