Congrats for your great work. I've been testing all the RubyMine 2.0 beta versions and finally I've just bought a license.
There's an issue that is happening in all versions, including the new RC1. I'm running RM on Ubuntu 8.10, using GTK+ as the Look&Feel. Sometimes, when a modal dialog appears, the keyboard seems not focused on the dialog. When I type, the keys go to the background window (the editor, the project view, etc.). There's no way to fill the text fields in the dialog, however I can click on the buttons with the mouse. This behaviour remains for all dialogs until I restart the IDE.
Have you had similar problems?