Limit the constraints that can be added from the facets

[lfoppiano]

I've added some random contraints from the facet, like for example:

and arrive to the following result (other facets are suffering the same):

[kermitt2]

I think it's ok. Only a few filters will already lead to 0 result, so we will never have so many filters in real life. The esthetic display of facets is not so important for a case that should never occur.

[lfoppiano]

OK, it's probably a small detail, I think the facets should be disabled when there are not results.

Moreover the user should not be able to click twice the same facet. E.g. selecing language = English should be possible only once.

[kermitt2]

I think you're absolutely right for these two other points! It could be two independent issues maybe.