Every so often, perhaps 25% of the time, if I double-click a word to highlight it SQLDeveloper hangs for about 15 seconds. I confirmed with a coworker that he is having the same issue. I am running Ubuntu 12.04 and he is running Windows 7. I am guessing this is related to the new logic that provides contextual clues in the GUI about that highlighted word, such as the purplish highlight of the same word other places in the document.