When I took my old Jav 1.4 source code, compiled+ran in Java 6 I solved old annoying issues like the infamous "Gray rect" bug. Also, the main menu and its sub menus had the same speed, BUT as soon as I jumped into the war screen and started painting frames on my map it went WAY slower than in 1.4 There was also delay on my mouse clicks events. It was so sluggish I cannot use it. I am using full screen API, passive rendering. Are there any things I should be checking and tweaking when jumping to Java 6, like SwingWorker and stuff? Are there any "Must haves" ? By the way, I paint my graphic on a JPanel (map, units, Fow, icons and stuff).