Card layout setup page messed up? [SOLVED by me ;-)]

Question

By mistake i pressed Add for my cards in the sprint while the page was loading, now it seems I am blocked, I cannot add anything, what gives?

Have tried refresh [F5] or [CTRL] + [F5] even enabled disabled add blockers :-(

The Field Name list and Add button shows up shortly during reload of the page, only to dissapear and be greyed out...

See Screen Shot:

Carsten Schwartz Nielsen · Accepted Answer

This is solved by me, it seems that you can have only three fields on the Cards.

It would have been nice with a hover text or other info indicating this in the GUI...

In this world, everything is a lesson ;-)