Hi, I'm new to Arduino and I just installed the official Arduino IDE from the Ubuntu Software Center. When I try to open a sketch with File-->Open, a blank, non-responsive windows appears. It does not close until I attempt to close it multiple times, and then the whole Arduino IDE closes, and I get an error message. :( The error message complains about a problem with Java. I don't have the error message right now, but if I get it again, I'll post it here.
I'm running Ubuntu 15.04. The Arduino IDE version is 2:1.0.5+dfsg2-4.