On the FC forum, you always gotta post. But when the post is too long, and you try to keep typing or editing the post, it starts to get glitchy. The longer your post is, the more glitchy it gets. Anyway, the only solution I know is to copy and paste rather than typing. You can't always do that though.
Lets say, for example, this post is 57 lines long. If I tried to edit it, it would glitch up. You could still edit it, it's just that the glitch is so annoying.