diff --git a/src/lib/y2firewall/widgets/allowed_services.rb b/src/lib/y2firewall/widgets/allowed_services.rb
index bcf569d8..b799c54c 100644
--- a/src/lib/y2firewall/widgets/allowed_services.rb
+++ b/src/lib/y2firewall/widgets/allowed_services.rb
@@ -92,6 +92,15 @@ def help
         )
       end
 
+      def validate
+        return true if selected_services.empty?
+        # TRANSLATORS: popup question
+        msg = _("The selection of services will be lost if you leave without\n" \
+          "applying the changes.\n\nDo you really want to continue?\n")
+
+        Yast::Popup.YesNo(msg)
+      end
+
     private
 
       # @!attribute [r] known_services_table
@@ -128,6 +137,10 @@ def refresh_services
         allowed_services_table.services = zone.services.clone
       end
 
+      def selected_services
+        known_services_table.selected_services + allowed_services_table.selected_services
+      end
+
       # Return a list of buttons to add/remove elements
       #
       # @return [Array<Yast::Term>] Buttons set UI terms
diff --git a/test/lib/y2firewall/widgets/allowed_services_test.rb b/test/lib/y2firewall/widgets/allowed_services_test.rb
old mode 100644
new mode 100755
index 6f3361e8..89ebdcc4
--- a/test/lib/y2firewall/widgets/allowed_services_test.rb
+++ b/test/lib/y2firewall/widgets/allowed_services_test.rb
@@ -60,6 +60,32 @@
       .with(widget_id: "allowed:#{zone.name}").and_return(allowed_svcs_table)
   end
 
+  describe "#validate" do
+    context "when no service has been selected" do
+      before do
+        allow(available_svcs_table).to receive(:selected_services).and_return([])
+        allow(allowed_svcs_table).to receive(:selected_services).and_return([])
+      end
+
+      it "returns true" do
+        expect(widget.validate).to eq(true)
+      end
+    end
+
+    context "when some service has been selected" do
+      it "warns the user about unsaved changed and ask for continuing" do
+        expect(Yast::Popup).to receive("YesNo").with(/Do you really want to continue/)
+        widget.validate
+      end
+
+      it "returns whether the user wanted to continue or not" do
+        expect(Yast::Popup).to receive("YesNo").and_return(false, true)
+        expect(widget.validate).to eq(false)
+        expect(widget.validate).to eq(true)
+      end
+    end
+  end
+
   describe "#handle" do
     context "when it receives an event to add a service" do
       let(:event) { { "ID" => :add } }