I find the focus behaviour of windows in Pybliographic unpleasant. That might depend on the window manager and user settings, I am using Gnome with Metacity and without sloppy focus, and Pybliographer 1.2.9 as packaged in Ubuntu. When the entry editor is open, it always stays on top of the main window, however it does not get focus when cycling through windows using Alt-Tab. This is especially annoying when filling an entry from information on a web page: you cannot switch between the browser and the editor using the keyboard, moreover the main window covers the browser window when editing. I think that using the standard focus behaviour for the editor window would be better (surely providing an option for this in the settings would be possible).

https://sourceforge.net/p/pybliographer/bugs/83/