I find i have this problem too but it is not the fault of the FL. My connection to the internet can be a little flakey at times so I sometimes have to reconnect to the router and renew my ADSL connection. I find that if this happens, leave FS running for 5 minutes and maximize the Flogger window, after a while, bingo, it re-appears. Try it, if it happens again, try opening up a Web Browser window and see if you have a connection to the net by going to a site that you rarely visit. (therefore it is not cached in your browser, I tend to use cnn.com or bbc.co.uk to prove this)
Hope this helps.
Phil