I played around with installing xulrunner 1.8.1.13+nobinonly-0ubuntu1 [universe] and setting "-vmargs -Dorg.eclipse.swt.browser.XULRunnerPath=/usr/lib/xulrunner/xulrunner" in eclipse.ini, and that cured the problem. Strangely, when I reverted the changes, thinks continue to work - which means that I currently cannot reproduce the bug any more.
I am suspecting that my Eclipse installation was not adapted to the new xulrunner directory, which was changed from /usr/lib/xulrunner-1.9b5 to /usr/lib/xulrunner-1.9.
I played around with installing xulrunner 1.8.1.13+ nobinonly- 0ubuntu1 [universe] and setting "-vmargs -Dorg.eclipse. swt.browser. XULRunnerPath= /usr/lib/ xulrunner/ xulrunner" in eclipse.ini, and that cured the problem. Strangely, when I reverted the changes, thinks continue to work - which means that I currently cannot reproduce the bug any more.
I am suspecting that my Eclipse installation was not adapted to the new xulrunner directory, which was changed from /usr/lib/ xulrunner- 1.9b5 to /usr/lib/ xulrunner- 1.9.