Limit on Pasting Characters to a Panel Component in GH *.051

Is anyine finding a limit on the number of characters one can paste to a panel component in GH? I am copying from a text file in Notepad.

I am trying to paste 1665 lines of text where each line is 80 characters long. I can only get as far as 505 lines.

One way to get round it would be to paste toa new text fiel and stream this file directly in to GH. However, I find the panel component more convenient for doing this.