Windows 7 have a nifty feature which combines the windows of opened applications under the same taskbar button. If you don't like it you can always turn it off.
If you are afraid of being hacked or someone else using your Facebook account you can enable option that will send you an email or text message in case your account has been accessed from a device that you never used before.
Knowing how to select parts of your Gimp documents with the help of Quick Mask might be one of the first things you should learn when starting with Gimp. Let me introduce you to the basics of Quick Mask.