OH, OK, I know what's going on.
You have to do TWO things to edit the title.
First, you click the edit button. That opens the window that allows you to edit the body of your thread.
To edit the title, you then have to click the "Go Advanced" button.
That will open an editing window that looks a lot more like the window you used to post the original message.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.