One of the most discussed Liferea behaviours is the tray icon/close button problem. Liferea allows you to have a notification area icon which indicates wether there are new downloaded headlines or not. When there are no new headlines the globe icon is a lighter shade and when there are new headlines it gets a darker shade. So the tray icon (if enabled in the preferences) is permanently visible. Clicking on the tray icon will hide or unhide Lifereas main window.
Now the dispute is about what should happen when the main windows close button (the one in the window manager decoration) is clicked. For Liferea this means the user requested to close the window and not the application. After all a "window close button" was clicked. Therefore with enabled tray icon closing the main window will not terminate Liferea. With disabled tray icon it will. The reasoning is that you requested removal of only one of two GUI elements of the application, therefore it is not to be terminated.
Of course one might argue wether it is correct to have a permanently visible tray icon, because it clutters the panel and the notification area was intented for notifications only. The big advantage of the notification area is that using it is portable accoss many desktop environments, which might not be true when implementing a panel applet e.g. for GNOME.