diff --git a/src/DesktopMagic/CalendarManagment.cs b/src/DesktopMagic/CalendarManagment.cs
index 0fff91f..6f326a9 100644
--- a/src/DesktopMagic/CalendarManagment.cs
+++ b/src/DesktopMagic/CalendarManagment.cs
@@ -41,7 +41,7 @@ namespace DesktopMagic
             }
 
             // Create Google Calendar API service.
-            var service = new CalendarService(new BaseClientService.Initializer()
+            CalendarService service = new CalendarService(new BaseClientService.Initializer()
             {
                 HttpClientInitializer = credential,
                 ApplicationName = ApplicationName,
diff --git a/src/DesktopMagic/CalendarWindow.xaml.cs b/src/DesktopMagic/CalendarWindow.xaml.cs
index c596e4d..3020bd7 100644
--- a/src/DesktopMagic/CalendarWindow.xaml.cs
+++ b/src/DesktopMagic/CalendarWindow.xaml.cs
@@ -68,7 +68,7 @@ namespace DesktopMagic
             base.OnSourceInitialized(e);
 
             //Set the window style to noactivate.
-            var helper = new WindowInteropHelper(this);
+            WindowInteropHelper helper = new WindowInteropHelper(this);
             WindowPos.SetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE,
             WindowPos.GetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE) | WindowPos.WS_EX_NOACTIVATE);
         }
diff --git a/src/DesktopMagic/CpuUsageWindow.xaml.cs b/src/DesktopMagic/CpuUsageWindow.xaml.cs
index 903aefb..8315df3 100644
--- a/src/DesktopMagic/CpuUsageWindow.xaml.cs
+++ b/src/DesktopMagic/CpuUsageWindow.xaml.cs
@@ -61,7 +61,7 @@ namespace DesktopMagic
             base.OnSourceInitialized(e);
 
             //Set the window style to noactivate.
-            var helper = new WindowInteropHelper(this);
+            WindowInteropHelper helper = new WindowInteropHelper(this);
             WindowPos.SetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE,
             WindowPos.GetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE) | WindowPos.WS_EX_NOACTIVATE);
         }
@@ -88,9 +88,10 @@ namespace DesktopMagic
 
         private void ValueTimer_Elapsed(object sender, ElapsedEventArgs e)
         {
+            string cpuUsage = GetCpuUsage();
             Dispatcher.Invoke(() =>
             {
-                textBlock.Text = GetCpuUsage();
+                textBlock.Text = cpuUsage;
             });
         }
 
diff --git a/src/DesktopMagic/DateWindow.xaml.cs b/src/DesktopMagic/DateWindow.xaml.cs
index 1d3e03e..96b2db3 100644
--- a/src/DesktopMagic/DateWindow.xaml.cs
+++ b/src/DesktopMagic/DateWindow.xaml.cs
@@ -48,7 +48,7 @@ namespace DesktopMagic
             base.OnSourceInitialized(e);
 
             //Set the window style to noactivate.
-            var helper = new WindowInteropHelper(this);
+            WindowInteropHelper helper = new WindowInteropHelper(this);
             WindowPos.SetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE,
             WindowPos.GetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE) | WindowPos.WS_EX_NOACTIVATE);
         }
diff --git a/src/DesktopMagic/MainWindow.xaml b/src/DesktopMagic/MainWindow.xaml
index 0cdac8e..c73257b 100644
--- a/src/DesktopMagic/MainWindow.xaml
+++ b/src/DesktopMagic/MainWindow.xaml
@@ -45,7 +45,7 @@
                 </DockPanel>
 
                 <DockPanel Grid.Column="1"  Margin="2.5,0,0,0">
-                    <ComboBox x:Name="optionsComboBox" DockPanel.Dock="Top" Height="24"  SelectedIndex="0" DisplayMemberPath="Item1" SelectionChanged="OptionsComboBox_SelectionChanged" Background="#FFECECEC" />
+                    <ComboBox x:Name="optionsComboBox" DockPanel.Dock="Top" Height="24"  SelectedIndex="0" DisplayMemberPath="Item1" SelectionChanged="OptionsComboBox_SelectionChanged" Background="#FFECECEC" Padding="4" VerticalAlignment="Center"/>
                     <ScrollViewer Background="#FFBBBBBB">
                         <Grid>
                             <StackPanel x:Name="optionsPanel" Margin="3,3,3,0" HorizontalAlignment="Stretch" Visibility="Collapsed" >
diff --git a/src/DesktopMagic/MainWindow.xaml.cs b/src/DesktopMagic/MainWindow.xaml.cs
index ef50509..f652e68 100644
--- a/src/DesktopMagic/MainWindow.xaml.cs
+++ b/src/DesktopMagic/MainWindow.xaml.cs
@@ -321,7 +321,7 @@ namespace DesktopMagic
                 EditCheckBox_Click(null, null);
                 this.ShowInTaskbar = false;
                 this.Visibility = Visibility.Collapsed;
-                foreach (var item in Windows)
+                foreach (Window item in Windows)
                 {
                     WindowPos.SendWpfWindowBack(item);
                     WindowPos.SendWpfWindowBack(item);
diff --git a/src/DesktopMagic/MusicVisualizerWindow.xaml.cs b/src/DesktopMagic/MusicVisualizerWindow.xaml.cs
index b835e6a..5244bb0 100644
--- a/src/DesktopMagic/MusicVisualizerWindow.xaml.cs
+++ b/src/DesktopMagic/MusicVisualizerWindow.xaml.cs
@@ -76,7 +76,7 @@ namespace DesktopMagic
             base.OnSourceInitialized(e);
 
             //Set the window style to noactivate.
-            var helper = new WindowInteropHelper(this);
+            WindowInteropHelper helper = new WindowInteropHelper(this);
             WindowPos.SetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE,
             WindowPos.GetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE) | WindowPos.WS_EX_NOACTIVATE);
         }
diff --git a/src/DesktopMagic/Plugin/PluginWindow.xaml.cs b/src/DesktopMagic/Plugin/PluginWindow.xaml.cs
index 07d0330..e433d46 100644
--- a/src/DesktopMagic/Plugin/PluginWindow.xaml.cs
+++ b/src/DesktopMagic/Plugin/PluginWindow.xaml.cs
@@ -146,7 +146,7 @@ namespace DesktopMagic
             Assembly dll = Assembly.Load(assemblyBytes);
             Type instanceType = dll.GetTypes().FirstOrDefault(type => type.GetTypeInfo().BaseType == typeof(Plugin));
 
-            foreach (var item in dll.GetTypes())
+            foreach (Type item in dll.GetTypes())
             {
                 Debug.WriteLine(item.Name);
                 Debug.WriteLine(typeof(Plugin).Name);
@@ -249,11 +249,14 @@ namespace DesktopMagic
                         valueTimer.Stop();
                     }
 
-                    //Update Image
-                    Dispatcher.Invoke(() =>
+                    if (result is not null)
                     {
-                        image.Source = BitmapToImageSource(result);
-                    });
+                        //Update Image
+                        Dispatcher.Invoke(() =>
+                        {
+                            image.Source = BitmapToImageSource(result);
+                        });
+                    }
                 }
             }
             catch (Exception ex)
diff --git a/src/DesktopMagic/TimeWindow.xaml.cs b/src/DesktopMagic/TimeWindow.xaml.cs
index 04132c8..e314cad 100644
--- a/src/DesktopMagic/TimeWindow.xaml.cs
+++ b/src/DesktopMagic/TimeWindow.xaml.cs
@@ -48,7 +48,7 @@ namespace DesktopMagic
             base.OnSourceInitialized(e);
 
             //Set the window style to noactivate.
-            var helper = new WindowInteropHelper(this);
+            WindowInteropHelper helper = new WindowInteropHelper(this);
             WindowPos.SetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE,
             WindowPos.GetWindowLong(helper.Handle, WindowPos.GWL_EXSTYLE) | WindowPos.WS_EX_NOACTIVATE);
         }