Perhaps try clearing the Java cache, and make sure you're using the latest version. I'm not sure what would cause such behaviour but it's almost certainly the Java applet that's causing it rather than anything on greenfoot.org directly.
I tried clearing Java cache, didn't work. I am using firefox 17 and java 7
You say you're using Firefox 17 - is this a stable release? A quick check on their website seems to list 15 as the stable version and 16 as the beta (I can only find reference to 17 in some nightly builds!) So if you really are using version 17 then you can probably expect it to be unstable - try using the latest stable version.
well, I tried it with firefox aurora(17) in my school, and the problem seems not to be in this release
It could be that your java is broken or that you have a virus. Why don't you run a complete scan on your computer using a virus scanner. If that all turns out OK, try uninstalling java JRE and reinstalling it, it might be outdated. Then check whether firefox is up-to-date.
Also make sure you are using stable editions of Java and Firefox.
Good luck.
Full Scan with avast, reinstalling java and and using firefox 15, the scenario pages still changes the behaviour
What kind of computer are you using? What are it's specs?
RAM, CPU, etc.
CPU: Intel Core i5-2430 (4 * 3 GHZ)
graphic card: Intel(R) HD Graphics 3000
Resolution: 1920 x 1080, 64 Bit
Mainboard: K73SV
OS: Win 7 Home
Ram: 8192MB
btw. this is a block I just copied for my pc, so don't wonder about more information that you want
Well, i thought you might be using some pc from '95 or so, but that is clearly not the point. Anyway, I have no idea what your problem could be, i'm out.
