diff --git a/app/views/gantts/show.html.erb b/app/views/gantts/show.html.erb
index 653a41d41..5d4ef0dbf 100644
--- a/app/views/gantts/show.html.erb
+++ b/app/views/gantts/show.html.erb
@@ -1,6 +1,7 @@
-<% form_tag(params.merge(:month => nil, :year => nil, :months => nil), :id => 'query_form') do %>
+<% form_tag(gantt_path(:month => params[:month], :year => params[:year], :months => params[:months]), :method => :put, :id => 'query_form') do %>
+ <%= hidden_field_tag('project_id', @project.to_param) if @project%>