While washing my car today, I noticed the gas door cover sliding while washing/drying. This was my first encounter with the gas door (wife’s car). So, I pushed it to open and was able to slide the panel off (it appears to be on a track). Is this how the explorers are designed or is this a defect? I have a MKX with same type of door and there is no movement whatsoever. The cover is sturdy and affixed to the hinge. Any thoughts/help would be appreciated. Thanks.