I made a red, white and blue block of the month quilt and have had some real trouble with the borders. I don't know if the fabric stretched (I cut it on the length of grain) or whether I am doing something wrong. I THOUGHT I measured correctly and actually took the borders off and remeasured and started again and it still is not perfectly flat altho' it is somewhat better. I mitered the corners and now I am wondering if the problem stems from the miters? HELP !