This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
This has happened to me about 5 times where I try to answer a question, spend some time typing or testing or whatever and when I finally hit submit, I get the login screen again, even though I already logged in. And if I log in at that time, my post disappears. So, I've learned to back up, copy my post and then login.