Another bug...

The routing daemon does not quit when marble quits. As a result you cannot use N9 as a USB mass storage device, because the routing daemon is using data from ~/MyDocs and therefore the vfat partition cannot be unmounted in order to switch to the mass storage mode when USB connected.

Solution 1: kill routing daemon when marble quits
Soultion 2: (additionally to #1) let the user decide where the routing and map cache data is stored. Use directory in ~/.local/share/marble/.... and make soft link to ~/MyDocs/.local/share/marble/...

Paul