"Minimize to tray" configuration option has really strange behavior on Ubuntu 11.10:

• When minimize is clicked, the window disappears (as expected)
• After that, if the tray icon is clicked in the notification area and "Open bitcoin" is selected to bring it back, the window does not come back; a bitcoin icon is added to the unity bar (on the left) though
• Clicking on this icon on the unity bar does nothing
• However, after switching focus to another program, the icon on the unity bar does bring the Bitcoin main window back

"Minimize on close" does work as expected. Clicking the "x" hides the window, and the tray icon can bring it back instantly.

BTW a pet peeve of mine is that these separate options are pretty confusing. Do we really them need both? It seems that most programs with similar background functionality implement "Minimize to tray on close".