You are doing it right. It did not start another thread.
Looking at the parts breakdown I am unable to determine what may be causing the center part to stick out.
Can you take a few pictures of it so I can see what you are working with? You can upload them to our servers here at JA.
Here is how you upload them-
At the top of your reply box is a icon that looks like a paper clip.
Click on the icon. It will bring up a box.
Click on browse. Another box will appear.
Click on browse again in that box.
Navigate to the place in your computer where the picture is. Select it, and then in the second box click on upload.
The second box will disapear. NOTE: You must wait for this to happen.
In the first box click on insert.
This will upload your picture, and you should see it displayed in your reply box.
Repeat the process to upload another picture.