With Duolingo you can learn languages for free! It's fun and effective.
Lately, things have been behaving weirdly in the translation area , panels are jumping around, sometimes a sentence panel will open, and display the same sentence twice, and sometimes I will refresh the page after doing a bunch of translations, only to have Duolingo say I didn't translate them, and when I translate the same sentences again, the coin icon says I gained another set of skill points, but the feedback box will say I did not because I "already say the best translation". Not to mention Duolingo not awarding me my rating points, even after refreshing the home page.
I have been having these problems exactly as you describe them for several weeks now. I wish I had an answer, but at least knowing someone else is having them helps me narrow down the issue, i.e., it's probably not my computer as I suspected. Which browser do you use?
Having the same problems and as far as my best guess goes, I think it's the combination of a slow server and the ajax asynchronous communication lagging behind. In other words, if I am right, this might take a while to correct, because it's gonna need some serious re-design...
Firefox Nightly 17, on Ubuntu Linux 12.04
I've had exactly these problems within the past few days, although only intermittently. I'm using Safari in Mac OS 10.5.8. So that would suggest it isn't a browser problem.
Sounds like a website bug to me.
I find that if a sentence is slow to open and you click again, that is when two boxes appear, and usually neither one works correctly. To avoid problems when this happens I skip to another sentence to close the faulty one and then go back to it later. Just a hint for dealing with this annoying problem.