Oh well. Just happened to me again. This time when I clicked on "Post" I lost everything and it went back to the same text as the inventory item I copied it from.
And i was thinking "Boy I had better click "Post" so I don't lose what I just typed", not knowing that would cause the exact thing I was trying to avoid.
Looks like I will still have to save everything I type in another ap because of this bug unless some one another idea.