diff --git a/app/helpers/calendars_helper.rb b/app/helpers/calendars_helper.rb
index cb13276..ec56abc 100644
--- a/app/helpers/calendars_helper.rb
+++ b/app/helpers/calendars_helper.rb
@@ -53,6 +53,6 @@ module CalendarsHelper
   end
 
   def link_to_month(link_name, year, month, options={})
-    link_to(link_name, params.merge(:year => year, :month => month), options)
+    link_to(link_name, {:params => request.query_parameters.merge(:year => year, :month => month)}, options)
   end
 end
diff --git a/app/helpers/gantt_helper.rb b/app/helpers/gantt_helper.rb
index 3c68cad..d49c60d 100644
--- a/app/helpers/gantt_helper.rb
+++ b/app/helpers/gantt_helper.rb
@@ -24,7 +24,7 @@ module GanttHelper
     when :in
       if gantt.zoom < 4
         link_to l(:text_zoom_in),
-          params.merge(gantt.params.merge(:zoom => (gantt.zoom + 1))),
+          {:params => request.query_parameters.merge(gantt.params.merge(:zoom => (gantt.zoom + 1)))},
           :class => 'icon icon-zoom-in'
       else
         content_tag(:span, l(:text_zoom_in), :class => 'icon icon-zoom-in').html_safe
@@ -33,7 +33,7 @@ module GanttHelper
     when :out
       if gantt.zoom > 1
         link_to l(:text_zoom_out),
-          params.merge(gantt.params.merge(:zoom => (gantt.zoom - 1))),
+          {:params => request.query_parameters.merge(gantt.params.merge(:zoom => (gantt.zoom - 1)))},
           :class => 'icon icon-zoom-out'
       else
         content_tag(:span, l(:text_zoom_out), :class => 'icon icon-zoom-out').html_safe
diff --git a/app/helpers/issues_helper.rb b/app/helpers/issues_helper.rb
index db94832..a276a61 100644
--- a/app/helpers/issues_helper.rb
+++ b/app/helpers/issues_helper.rb
@@ -290,7 +290,7 @@ module IssuesHelper
   def query_links(title, queries)
     return '' if queries.empty?
     # links to #index on issues/show
-    url_params = controller_name == 'issues' ? {:controller => 'issues', :action => 'index', :project_id => @project} : params
+    url_params = controller_name == 'issues' ? {:controller => 'issues', :action => 'index', :project_id => @project} : {}
 
     content_tag('h3', title) + "\n" +
       content_tag('ul',
diff --git a/app/views/activities/index.html.erb b/app/views/activities/index.html.erb
index d3a780f..26613ae 100644
--- a/app/views/activities/index.html.erb
+++ b/app/views/activities/index.html.erb
@@ -25,12 +25,12 @@
   <ul class="pages">
     <li class="previous page">
 <%= link_to("\xc2\xab " + l(:label_previous),
-                   params.merge(:from => @date_to - @days - 1),
+                   {:params => request.query_parameters.merge(:from => @date_to - @days - 1)},
                    :title => l(:label_date_from_to, :start => format_date(@date_to - 2*@days), :end => format_date(@date_to - @days - 1)),
                    :accesskey => accesskey(:previous)) %>
     </li><% unless @date_to >= User.current.today %><li class="next page">
 <%= link_to(l(:label_next) + " \xc2\xbb",
-                   params.merge(:from => @date_to + @days - 1),
+                   {:params => request.query_parameters.merge(:from => @date_to + @days - 1)},
                    :title => l(:label_date_from_to, :start => format_date(@date_to), :end => format_date(@date_to + @days - 1)),
                    :accesskey => accesskey(:next)) %><% end %>
     </li>
diff --git a/app/views/gantts/show.html.erb b/app/views/gantts/show.html.erb
index 1337fef..0f70920 100644
--- a/app/views/gantts/show.html.erb
+++ b/app/views/gantts/show.html.erb
@@ -333,12 +333,12 @@
 <tr>
   <td style="text-align:left;">
     <%= link_to("\xc2\xab " + l(:label_previous),
-                               params.merge(@gantt.params_previous),
+                               {:params => request.query_parameters.merge(@gantt.params_previous)},
                                :accesskey => accesskey(:previous)) %>
   </td>
   <td style="text-align:right;">
     <%= link_to(l(:label_next) + " \xc2\xbb",
-                               params.merge(@gantt.params_next),
+                               {:params => request.query_parameters.merge(@gantt.params_next)},
                                :accesskey => accesskey(:next)) %>
   </td>
 </tr>