Cleaning and a bit of telfon oil on the sides can help in some cases. Take the slide plate completely off. There is a curved spring with a screw in center. The curve will have less tension on the plate when it's fully down. If it's still tight when the screw is fully turned in, you can slightly bend the sides of the spring inward. Be carefull, just a bit, and then try it with the slide plate on. The screw is ment to be fully turned in, but they can sometimes become a bit loose.