Category 'more than one'

[PanderMusubi]

Next to the category Uncategorized, please offer a category called More than one. This will list all contacts that have more than one category.

Many users only want to add a contact to only one category and this function will enable finding quickly which contacts have more than one category.

This also helps #20

[PanderMusubi]

Another name for this function could be Multiple categories.

[jobisoft]

I like that. Wanna give it a try and implement that on your own?

[PanderMusubi]

Sorry, no thank you, too busy with other FOSS. I did contribute improvements to the Dutch translation in #42

[jobisoft]

Thanks for your contribution!