diff --git a/app/controllers/cost_reports_controller.rb b/app/controllers/cost_reports_controller.rb
index 7089cec1f0..fd8bff09dd 100644
--- a/app/controllers/cost_reports_controller.rb
+++ b/app/controllers/cost_reports_controller.rb
@@ -112,16 +112,54 @@ class CostReportsController < ApplicationController
   ##
   # Set a default query to cut down initial load time
   def default_filter_parameters
-    { operators: { user_id: '=', spent_on: '>d' },
+    {
+      operators: { user_id: '=', spent_on: '>d' },
       values: { user_id: [User.current.id], spent_on: [30.days.ago.strftime('%Y-%m-%d')] }
     }.tap do |hash|
       if @project
-        hash[:operators].merge! project_id: '='
-        hash[:values].merge! project_id: [@project.id]
+        set_project_filter(hash, @project.id)
       end
     end
   end
 
+  ##
+  # Get the filter params with an optional project context
+  def filter_params
+    filters = super
+    update_project_context!(filters)
+
+    filters
+  end
+
+  ##
+  # Clear the query if the project context changed
+  def update_project_context!(filters)
+
+    # Only in project context
+    return unless @project
+
+    # Only if the project context changed
+    context = filters[:project_context]
+
+    # Context is same, don't set project (allow override)
+    return if context == @project.id
+
+    # Reset context if project missing
+    if context.nil?
+      filters[:project_context] = @project.id
+      return
+    end
+
+    # Update the project context and project_id filter
+    set_project_filter(filters, @project.id)
+  end
+
+  def set_project_filter(filters, project_id)
+    filters[:project_context] = project_id
+    filters[:operators].merge! project_id: '='
+    filters[:values].merge! project_id: [project_id]
+  end
+
   ##
   # Set a default query to cut down initial load time
   def default_group_parameters
@@ -134,23 +172,6 @@ class CostReportsController < ApplicationController
     end
   end
 
-  ##
-  # We apply a project filter, except when we are just applying a brand new query
-  def ensure_project_scope!(filters)
-    return unless ensure_project_scope?
-    if @project
-      filters[:operators].merge! project_id: '='
-      filters[:values].merge! project_id: @project.id.to_s
-    else
-      filters[:operators].delete :project_id
-      filters[:values].delete :project_id
-    end
-  end
-
-  def ensure_project_scope?
-    !(set_filter? or set_unit?)
-  end
-
   ##
   # Determine active cost types, the currently selected unit and corresponding cost type
   def set_cost_types
diff --git a/spec/controllers/cost_reports_controller_spec.rb b/spec/controllers/cost_reports_controller_spec.rb
index a563f3b237..83c0a2f576 100644
--- a/spec/controllers/cost_reports_controller_spec.rb
+++ b/spec/controllers/cost_reports_controller_spec.rb
@@ -34,7 +34,7 @@ describe CostReportsController, type: :controller do
     describe "WHEN providing invalid units
               WHEN having the view_cost_entries permission" do
       before do
-        get :show, id: 1, unit: -1
+        get :show, params: { id: 1, unit: -1 }
       end
 
       it "should respond with a 404 error" do
diff --git a/spec/controllers/custom_fields_controller_spec.rb b/spec/controllers/custom_fields_controller_spec.rb
index 0c93181493..ad7d2e771f 100644
--- a/spec/controllers/custom_fields_controller_spec.rb
+++ b/spec/controllers/custom_fields_controller_spec.rb
@@ -54,7 +54,7 @@ describe CustomFieldsController do
         cost_query.group_by(custom_field_permanent_name)
         cost_query.save!
 
-        delete :destroy, id: custom_field.id
+        delete :destroy, params: { id: custom_field.id }
       end
     end
 
diff --git a/spec/features/project_context_spec.rb b/spec/features/project_context_spec.rb
new file mode 100644
index 0000000000..85c0965338
--- /dev/null
+++ b/spec/features/project_context_spec.rb
@@ -0,0 +1,24 @@
+require 'spec_helper'
+require_relative 'support/pages/cost_report_page'
+
+describe 'Cost report project context', type: :feature, js: true do
+  let(:project1) { FactoryGirl.create :project }
+  let(:project2) { FactoryGirl.create :project }
+  let(:admin) { FactoryGirl.create :admin }
+
+  let(:report_page) { ::Pages::CostReportPage.new project }
+
+  before do
+    project1
+    project2
+    login_as admin
+  end
+
+  it "switches the project context when visiting another project's cost report" do
+    visit cost_reports_path(project1)
+    expect(page).to have_selector('#project_id_arg_1_val option', text: project1.name)
+
+    visit cost_reports_path(project2)
+    expect(page).to have_selector('#project_id_arg_1_val option', text: project2.name)
+  end
+end
\ No newline at end of file