[tarisea]

I've been using this feature for a long time and it has always worked fine. Suddenly any time I try to add or change anything I receive the following error "Unhandled exception: <b>TypeError</b>:sequence item 0: expected string or Unicode, NoneType found"

Copy to clipboard gives the following info:

calibre, version 2.9.0
ERROR: Unhandled exception: <b>TypeError</b>:sequence item 0: expected string or Unicode, NoneType found

calibre 2.9 isfrozen: True is64bit: False
Windows-7-6.1.7601-SP1 Windows ('32bit', 'WindowsPE')
32bit process running on 64bit windows
('Windows', '7', '6.1.7601')
Python 2.7.8
Windows: ('7', '6.1.7601', 'SP1', 'Multiprocessor Free')
Successfully initialized third party plugins: DeDRM && Find Duplicates && iOS reader applications && Favourites Menu && Barnes & Noble && Goodreads && User Category && Derive_Genres && Search The Internet && Marvin XD && Goodreads Sync && Quality Check
Traceback (most recent call last):
File "site-packages\calibre\gui2\preferences\main.py", line 341, in commit
File "site-packages\calibre\gui2\preferences\look_feel.py", line 460, in commit
File "site-packages\calibre\gui2\preferences\coloring.py", line 1035, in commit
File "site-packages\calibre\gui2\preferences\coloring.py", line 740, in commit
File "site-packages\calibre\library\coloring.py", line 60, in template
TypeError: sequence item 0: expected string or Unicode, NoneType found

I tried repairing the install but it didn't help. Any idea what's happening?

Thanks
TTRS