DPR Lines Problem When Replying With Quote

Does anyone else get these weird and annoying lines when Replying With Quote? They only happen when there is quite a lot of text to the post that you are replying to and your reply is down at the bottom of the text box. I am using Firefox on a PC.  You can still reply and type a message but as you can imagine it's quite difficult to see it as you type over the lines. I have had this problem for less than a week.