Text box width when big block of text is pasted into message body

I noticed a difference in the way the message box is formatted when I pasted a big block of text from a log file for one of my messages.

If I type the text the box width is shown normal, as you see here. But if I paste a big block of text, the box expands and reading the text becomes difficult.

Has anyone reported this before.

It is quiet a pain to read such a block when the horizontal scroll bar is not displayed.

Any comments ?

Devendra