fix double click ui when no cam found

MainForm.cs

@@ -117,9 +117,12 @@ namespace robospot_camera_finder
         }
 
         private void lbMain_MouseDoubleClick(object sender, MouseEventArgs e)
+        {
+            if (lbMain.SelectedItem != null)
             {
                 Form viewer = new StreamViewer(lbMain.GetItemText(lbMain.SelectedItem), lbMain.SelectedValue.ToString());
                 viewer.Show();
             }
         }
     }
+}

robospot-camera-finder.csproj

@@ -7,8 +7,14 @@
     <Nullable>enable</Nullable>
     <UseWindowsForms>true</UseWindowsForms>
     <ImplicitUsings>enable</ImplicitUsings>
+    <StartupObject>robospot_camera_finder.Program</StartupObject>
+    <ApplicationIcon>favicon.ico</ApplicationIcon>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Content Include="favicon.ico" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Haukcode.sACN" Version="2.0.19" />
     <PackageReference Include="LibVLCSharp" Version="3.8.2" />