An idea if it happens again for you ....

I use the regular reply button most of the time, not the quick reply. internet explorer and and google crome allows you to set your settings so that your window has more than one tab.

I have mine set at two tabs. that way when I am posting /pming someone I have the reply in one tab and I open the second tab to Psych Central and find the post I am replying to, now I can go back and forth between the two tabs one with the post in it and one where Im writing the reply. when Im done writing and submitting my reply I close out the second window or put the second window on the psych central index so that its ready for my next post.