Create new data grid result object each time, so it's of the right vendor type. Fixes an access violation when switching to a table in another connection. See http://www.heidisql.com/forum.php?t=8306

source/main.pas

@@ -4023,9 +4023,12 @@ begin
 
     try
       ShowStatusMsg('Fetching rows ...');
-      if not Assigned(DataGridResult) then
+      // Result object must be of the right vendor type
+      if not RefreshingData then begin
+        FreeAndNil(DataGridResult);
         DataGridResult := DBObj.Connection.Parameters.CreateQuery(Self);
-      DataGridResult.Connection := ActiveConnection;
+      end;
+      DataGridResult.Connection := DBObj.Connection;
       DataGridResult.SQL := Select;
       DataGridResult.Execute(Offset > 0);
       DataGridResult.ColumnOrgNames := WantedColumnOrgnames;