I've got a Joomla 3.4.8 installed with a few templates and Phoca Gallery 4.2.2. We decided to use the template "Music free" as default (gavick.com/joomla-templates/music-free).
Unfortunately, any inserted geo-tagging GoogleMaps is displayed only gray. However, you can navigate, zoom, etc. Firefoxes network monitor shows, that new tiles are loaded from google's server. When I switch to another theme for such a page including a geo-tagging map, it works flawlessly. Also tested on different computers, different browsers, and different connections - no change in behaviour.
I cannot see any javascript error, the network monitor tells that all tiles are loaded in each scenario, and as far as I understand it, there is no CSS problem either. Maybe you have any quick hints or could name tools which might help me to find the issue?
Here are some screenshots:
Map is gray in "music free" theme; pins are located correctly; map is responsive; network monitor shows traffic when I pan or zoom or interact generally.
Also note, that the zoom-controls and the street-view-guy are not displayed in the bottom right corner.

http://fs5.directupload.net/images/160113/xzbflqvr.png
Working perfectly in another theme, here "Allrounder":

http://fs5.directupload.net/images/160113/dfammh5a.png
In case it does NOT work, this is what the Firefox network monitor shows as traffic to google:

http://fs5.directupload.net/images/160113/x2pkrnbf.png
In case it DOES work, the traffic looks like this:

http://fs5.directupload.net/images/160113/at7b7kcw.png
The code that is inserted by Phoca Gallery to display the map is exactly the same with both themes.
However, the themes have different containers wrapped around.
Thats the tree view to the first tile of the map, which I selected to see its CSS properties (case 'does NOT work'):

The tree expanded to the first map tile in the case it DOES work:

I would appreciate any help, already spent too many hours searching and debugging...
Thanks in advance guys,
Greetings Flo

