To everyone experiencing the not being allowed to zoom out bug. All I did to "fix" my problem was to hit the cartographer button on the map, go to look 'n' feel, then uncheck the lock option. The map stop becoming transparent to clicks and you are allowed to zoom in and zoom out. Hope this helps.
When you use "Alternate-Map" Option it works again, too. (I bound a key to the Alternate-Map option in Keybindings and ... it works) So i think the "problem" was that somehow the map gets switched to Alternate-Map mode ..... as simple as that ;-)