keep current branch when switch from tree to commits

app/views/layouts/_project_side.html.haml

+.project-sidebar
+  .fixed
+    %aside
+      = link_to project_path(@project), :class => project_tab_class do 
+        Project
+
+      - if @project.repo_exists?
+        = link_to "Repository", project_repository_path(@project), :class => repository_tab_class
+        = link_to "Tree", tree_project_ref_path(@project, @ref || @project.root_ref), :class => tree_tab_class
+        = link_to "Commits", project_commits_path(@project, :ref => (@ref || @project.root_ref)), :class => (controller.controller_name == "commits") ? "current" : nil
+        = link_to "Network", graph_project_path(@project), :class => current_page?(:controller => "projects", :action => "graph", :id => @project) ? "current" : nil
+        = link_to  project_issues_filter_path(@project), :class => (controller.controller_name == "issues") ? "current" : nil do
+          Issues
+        = link_to wall_project_path(@project), :class => current_page?(:controller => "projects", :action => "wall", :id => @project) ? "current" : nil do
+          Wall
+          - if @project.common_notes.today.count > 0
+            %span{ :class => "number" }= @project.common_notes.today.count
+        = link_to project_merge_requests_path(@project), :class => (controller.controller_name == "merge_requests") ? "current" : nil do
+          Requests

app/views/layouts/project.html.haml

@@ -18,29 +18,7 @@
     = render :partial => "layouts/flash"
     #container
       = render :partial => "layouts/head_panel"
-      -#= render :partial => "layouts/middle_panel" if @project && !@project.new_record?
       .project-container
-        .project-sidebar
-          .fixed
-            %aside
-              = link_to project_path(@project), :class => project_tab_class do 
-                Project
-
-              - if @project.repo_exists?
-                = link_to "Repository", project_repository_path(@project), :class => repository_tab_class
-                = link_to "Tree", tree_project_ref_path(@project, @ref || @project.root_ref), :class => tree_tab_class
-                = link_to "Commits", project_commits_path(@project), :class => (controller.controller_name == "commits") ? "current" : nil
-                = link_to "Network", graph_project_path(@project), :class => current_page?(:controller => "projects", :action => "graph", :id => @project) ? "current" : nil
-                = link_to  project_issues_filter_path(@project), :class => (controller.controller_name == "issues") ? "current" : nil do
-                  Issues
-                = link_to wall_project_path(@project), :class => current_page?(:controller => "projects", :action => "wall", :id => @project) ? "current" : nil do
-                  Wall
-                  - if @project.common_notes.today.count > 0
-                    %span{ :class => "number" }= @project.common_notes.today.count
-                = link_to project_merge_requests_path(@project), :class => (controller.controller_name == "merge_requests") ? "current" : nil do
-                  Requests
-
-
-
+        = render :partial => "layouts/project_side"
         .project-content
           = yield