Make status selectable

[hermannkm]

At the moment each status which contains issues is shown in dashboard as a column. I think it would be nice to be able to additionally select a status on/off independently especially in "All Projects" view.

This would be nice for me as I have scrum projects using a "Backlog" status whereas standard projects do not.

[akpaevj]

I will try to implement this feature in the next release