Ok, seem to have found a way to a solution:
Will report back if I run into trouble again… and, oh yeah, the “read only icon has disappeared”… 
From Jim here:
BLUEFROG
fillmore
Control-click and remove it from the Finder’s sidebar then install it again from DEVONthink 3 > Install Add-Ons … and do not rename the sidebar alias (in case you did or wanted to) .