kiwidude,
I just installed 1.5.9 and restarted. Clicking the 'Customize...' button errors for me:
Code:
calibre, version 0.9.21
ERROR: Unhandled exception: <b>NotImplementedError</b>:
Traceback (most recent call last):
File "calibre_plugins.generate_cover.dialogs", line 1675, in show_configuration
File "site-packages\calibre\customize\__init__.py", line 175, in do_user_config
File "site-packages\calibre\customize\__init__.py", line 246, in customization_help
NotImplementedError