Merged r3379 from trunk.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/0.9-stable@3387 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/controllers/issues_controller.rb

@@ -359,6 +359,7 @@ def destroy
   def gantt
     @gantt = Redmine::Helpers::Gantt.new(params)
     retrieve_query
+    @query.group_by = nil
     if @query.valid?
       events = []
       # Issues that have start and due dates
@@ -398,6 +399,7 @@ def calendar
 
     @calendar = Redmine::Helpers::Calendar.new(Date.civil(@year, @month, 1), current_language, :month)
     retrieve_query
+    @query.group_by = nil
     if @query.valid?
       events = []
       events += @query.issues(:include => [:tracker, :assigned_to, :priority],