diff --git a/app/assets/javascripts/users/calendar.js b/app/assets/javascripts/users/calendar.js
index 6d739039a5b..ba7f533c349 100644
--- a/app/assets/javascripts/users/calendar.js
+++ b/app/assets/javascripts/users/calendar.js
@@ -206,6 +206,7 @@
           }
         });
       } else {
+        this.currentSelectedDate = '';
         return $('.user-calendar-activities').html('');
       }
     };
diff --git a/changelogs/unreleased/disable-calendar-deselection.yml b/changelogs/unreleased/disable-calendar-deselection.yml
new file mode 100644
index 00000000000..060797bba34
--- /dev/null
+++ b/changelogs/unreleased/disable-calendar-deselection.yml
@@ -0,0 +1,4 @@
+---
+title: Fix deselecting calendar days on contribution graph
+merge_request: 6453
+author: ClemMakesApps
diff --git a/spec/features/calendar_spec.rb b/spec/features/calendar_spec.rb
index 7fa0c95cae2..3e0b6364e0d 100644
--- a/spec/features/calendar_spec.rb
+++ b/spec/features/calendar_spec.rb
@@ -52,6 +52,10 @@ feature 'Contributions Calendar', js: true, feature: true do
     Event.create(push_params)
   end
 
+  def get_first_cell_content
+    find('.user-calendar-activities').text
+  end
+
   before do
     login_as :user
     visit @user.username
@@ -62,6 +66,43 @@ feature 'Contributions Calendar', js: true, feature: true do
     expect(page).to have_css('.js-contrib-calendar')
   end
 
+  describe 'select calendar day', js: true do
+    let(:cells) { page.all('.user-contrib-cell') }
+    let(:first_cell_content_before) { get_first_cell_content }
+
+    before do
+      cells[0].click
+      wait_for_ajax
+      first_cell_content_before
+    end
+
+    it 'displays calendar day activities', js: true do
+      expect(get_first_cell_content).not_to eq('')
+    end
+
+    describe 'select another calendar day', js: true do
+      before do
+        cells[1].click
+        wait_for_ajax
+      end
+
+      it 'displays different calendar day activities', js: true do
+        expect(get_first_cell_content).not_to eq(first_cell_content_before)
+      end
+    end
+
+    describe 'deselect calendar day', js: true do
+      before do
+        cells[0].click
+        wait_for_ajax
+      end
+
+      it 'hides calendar day activities', js: true do
+        expect(get_first_cell_content).to eq('')
+      end
+    end
+  end
+
   describe '1 calendar activity' do
     before do
       Issues::CreateService.new(contributed_project, @user, issue_params).execute