attribute table manager fails to start from new mapset, see https://trac.osgeo.org/grass/ticket/3658

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@73390 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/lmgr/frame.py

@@ -1083,6 +1083,10 @@ class GMFrame(wx.Frame):
                              parent=self,
                              flags='c',
                              mapset=mapset)
+            # ensure that DB connection is defined
+            ret += RunCommand('db.connect',
+                              parent=self,
+                              flags='c')
             if ret == 0:
                 GMessage(parent=self,
                          message=_("Current mapset is <%s>.") % mapset)