You're very welcome! I'm so glad it worked for you too!! I never realized just how much I relied on opening my inventory until this happened to me. I'm also back to playing with friends again which is the best thing about Minecraft. Hopefully they can look into it and fix the issue so it doesn't occur again. Happy Crafting Dorothy!
Dorothy, I fixed mine last night! After exhausting all other options I finally thought of something unconventional that I hadn't tried yet: killing myself. So as night fell I walked outside and found a brave looking skeleton archer. Well I just stood there playing chicken with his arrows. Oddly enough, after the skeleton archer had killed me, my inventory worked great again.
So, my recommendation would be to kill your character in some way, shape or form to see if that fixes the problem. I wonder if there was a corruption in the respawn. I hope this helps you!
Opened this world in the latest snapshot to try and replicate this problem and it has been completely resolved. There're no memory problems any more and everything runs smoothly.