History: ExplodingPagesBug

When I copy and paste text into a wiki page from a text editor such as Wordpad, the center column that contains the wiki page content expands so I have to scroll to the right to read all of it. It pushes the right (third) column to the right along with it. Typing directly into the wiki page Edit box does not produce the error.

I found that, when I have this error, if I copy the text from the wiki Edit box (such as the one I am now typing into), then paste it into an HTML editor and replace every <p> with <br><br> (and of course remove every </p>) then paste it back into the wiki Edit box and save, the center column/wiki page does not "explode" to the right, and all three columns fit nicely on the screen.