In "Options/Customize key bindings" a window opens showing the key bindings. It looks as if key bindings could be modified here. Indeed, if I highlight a line, press "Grab", and enter a key combination, this is entered in the column "Shurtcut". If I press the "OK" button, the newly entered key is not active, not even after a restart. Moreover, if I enter the Key bindings windows again, the old key binding is displayed.
Intriguingly, if I open the "Key bindings" window an do not change any setting, and the press "OK", an information window appears "Your key bindings have been stored. You must restart JabRef for the new key binding to work properly." Obviously, nothing is changed after a restart.
Should be solved via PR https://github.com/JabRef/jabref/pull/35
Even with the PR, the settings aren't saved.
Just to make it clear: This is still an issue occuring in version 2.10. Running Debian Version 8 (jessie).
There is also a language issue. In my case, entering a new key binding such as "ctrl C" is translated into german -> "strg C". Possibly this is related to the error.