diff --git a/Greenshot/Drawing/Fields/FieldAggregator.cs b/Greenshot/Drawing/Fields/FieldAggregator.cs
index e9ba4b282..0bbd395d3 100644
--- a/Greenshot/Drawing/Fields/FieldAggregator.cs
+++ b/Greenshot/Drawing/Fields/FieldAggregator.cs
@@ -153,7 +153,7 @@ namespace Greenshot.Drawing.Fields
 		{
 			ClearFields();
 			internalUpdateRunning = true;
-			foreach (Field field in FindCommonFields())
+			foreach (var field in FindCommonFields())
 			{
 				SetFieldValue(field.FieldType, field.Value);
 			}
diff --git a/Greenshot/Drawing/Surface.cs b/Greenshot/Drawing/Surface.cs
index 12199733d..cc727eb7b 100644
--- a/Greenshot/Drawing/Surface.cs
+++ b/Greenshot/Drawing/Surface.cs
@@ -1910,7 +1910,7 @@ namespace Greenshot.Drawing
 			FieldAggregator.UnbindElement(container);
 			if (generateEvents && _movingElementChanged != null)
 			{
-				SurfaceElementEventArgs eventArgs = new SurfaceElementEventArgs {Elements = selectedElements};
+				var eventArgs = new SurfaceElementEventArgs {Elements = selectedElements};
 				_movingElementChanged(this, eventArgs);
 			}
 		}
diff --git a/Greenshot/Drawing/TextContainer.cs b/Greenshot/Drawing/TextContainer.cs
index 18a3e66f6..84deb9868 100644
--- a/Greenshot/Drawing/TextContainer.cs
+++ b/Greenshot/Drawing/TextContainer.cs
@@ -56,7 +56,8 @@ namespace Greenshot.Drawing
 		/// The StringFormat object is not serializable!!
 		/// </summary>
 		[NonSerialized]
-		StringFormat _stringFormat = new StringFormat();
+		private StringFormat _stringFormat = new StringFormat();
+
 		public StringFormat StringFormat => _stringFormat;
 
 		// Although the name is wrong, we can't change it due to file serialization
@@ -172,8 +173,13 @@ namespace Greenshot.Drawing
 			Height = textSize.Height + lineThickness;
 		}
 
-		void TextContainer_PropertyChanged(object sender, PropertyChangedEventArgs e)
+		private void TextContainer_PropertyChanged(object sender, PropertyChangedEventArgs e)
 		{
+			if (_textBox == null)
+			{
+				return;
+			}
+
 			if (_textBox.Visible)
 			{
 				_textBox.Invalidate();
@@ -203,7 +209,7 @@ namespace Greenshot.Drawing
 			}
 		}
 
-		void TextContainer_FieldChanged(object sender, FieldChangedEventArgs e)
+		private void TextContainer_FieldChanged(object sender, FieldChangedEventArgs e)
 		{
 			if (_textBox == null)
 			{
@@ -467,7 +473,7 @@ namespace Greenshot.Drawing
 			_textBox.ForeColor = lineColor;
 		}
 
-		void textBox_KeyDown(object sender, KeyEventArgs e)
+		private void textBox_KeyDown(object sender, KeyEventArgs e)
 		{
 			// ESC and Enter/Return (w/o Shift) hide text editor
 			if (e.KeyCode == Keys.Escape || ((e.KeyCode == Keys.Return || e.KeyCode == Keys.Enter) && e.Modifiers == Keys.None))
@@ -477,7 +483,7 @@ namespace Greenshot.Drawing
 			}
 		}
 
-		void textBox_LostFocus(object sender, EventArgs e)
+		private void textBox_LostFocus(object sender, EventArgs e)
 		{
 			// next change will be made undoable
 			makeUndoable = true;
diff --git a/Greenshot/Memento/DrawableContainerBoundsChangeMemento.cs b/Greenshot/Memento/DrawableContainerBoundsChangeMemento.cs
index 48b94e91c..37564b694 100644
--- a/Greenshot/Memento/DrawableContainerBoundsChangeMemento.cs
+++ b/Greenshot/Memento/DrawableContainerBoundsChangeMemento.cs
@@ -80,7 +80,7 @@ namespace Greenshot.Memento
 			var other = otherMemento as DrawableContainerBoundsChangeMemento;
 			if (other != null)
 			{
-				if (Objects.CompareLists<IDrawableContainer>(listOfdrawableContainer, other.listOfdrawableContainer))
+				if (ObjectExtensions.CompareLists<IDrawableContainer>(listOfdrawableContainer, other.listOfdrawableContainer))
 				{
 					// Lists are equal, as we have the state already we can ignore the new memento
 					return true;
diff --git a/GreenshotPlugin/Core/Objects.cs b/GreenshotPlugin/Core/ObjectExtensions.cs
similarity index 60%
rename from GreenshotPlugin/Core/Objects.cs
rename to GreenshotPlugin/Core/ObjectExtensions.cs
index 8a56ea73c..0e31fd5d5 100644
--- a/GreenshotPlugin/Core/Objects.cs
+++ b/GreenshotPlugin/Core/ObjectExtensions.cs
@@ -18,6 +18,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -26,7 +27,10 @@ using System.Runtime.Serialization;
 using System.Runtime.Serialization.Formatters.Binary;
 
 namespace GreenshotPlugin.Core {
-	public static class Objects {
+	/// <summary>
+	/// Extension methods which work for objects
+	/// </summary>
+	public static class ObjectExtensions {
 	
 		/// <summary>
 		/// Perform a deep Copy of the object.
@@ -34,41 +38,56 @@ namespace GreenshotPlugin.Core {
 		/// <typeparam name="T">The type of object being copied.</typeparam>
 		/// <param name="source">The object instance to copy.</param>
 		/// <returns>The copied object.</returns>
-		public static T Clone<T>(this T source) {
-			if (!typeof(T).IsSerializable) {
-				throw new ArgumentException("The type must be serializable.", "source");
+		public static T Clone<T>(this T source)
+		{
+			var typeparam = typeof(T);
+			if (!typeparam.IsInterface && !typeparam.IsSerializable)
+			{
+				throw new ArgumentException("The type must be serializable.", nameof(source));
 			}
-	
+
 			// Don't serialize a null object, simply return the default for that object
-			if (ReferenceEquals(source, null)) {
+			if (source == null) {
 				return default(T);
 			}
 	
 			IFormatter formatter = new BinaryFormatter();
-			Stream stream = new MemoryStream();
-			using (stream) {
+			using (var stream = new MemoryStream()) {
 				formatter.Serialize(stream, source);
 				stream.Seek(0, SeekOrigin.Begin);
 				return (T)formatter.Deserialize(stream);
 			}
 		}
 	
+		/// <summary>
+		/// Clone the content from source to destination
+		/// </summary>
+		/// <typeparam name="T">Type to clone</typeparam>
+		/// <param name="source">Instance to copy from</param>
+		/// <param name="destination">Instance to copy to</param>
 		public static void CloneTo<T>(this T source, T destination) {
-			Type type = typeof(T);
-			FieldInfo[] myObjectFields = type.GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
+			var type = typeof(T);
+			var myObjectFields = type.GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
 
-			foreach (FieldInfo fi in myObjectFields) {
-				fi.SetValue(destination, fi.GetValue(source));
+			foreach (var fieldInfo in myObjectFields) {
+				fieldInfo.SetValue(destination, fieldInfo.GetValue(source));
 			}
-			PropertyInfo[] myObjectProperties = type.GetProperties(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
+			var myObjectProperties = type.GetProperties(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
 
-			foreach (PropertyInfo pi in myObjectProperties) {
-				if (pi.CanWrite) {
-					pi.SetValue(destination, pi.GetValue(source, null), null);
+			foreach (var propertyInfo in myObjectProperties) {
+				if (propertyInfo.CanWrite) {
+					propertyInfo.SetValue(destination, propertyInfo.GetValue(source, null), null);
 				}
 			}
 		}
-		
+
+		/// <summary>
+		/// Compare two lists
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="l1">IList</param>
+		/// <param name="l2">IList</param>
+		/// <returns>true if they are the same</returns>
 		public static bool CompareLists<T>(IList<T> l1, IList<T> l2) {
 			if (l1.Count != l2.Count) {
 				return false;
diff --git a/GreenshotPlugin/GreenshotPlugin.csproj b/GreenshotPlugin/GreenshotPlugin.csproj
index b26c5c405..608c8a10b 100644
--- a/GreenshotPlugin/GreenshotPlugin.csproj
+++ b/GreenshotPlugin/GreenshotPlugin.csproj
@@ -189,7 +189,7 @@
     <Compile Include="Core\LogHelper.cs" />
     <Compile Include="Core\NetworkHelper.cs" />
     <Compile Include="Core\OAuthHelper.cs" />
-    <Compile Include="Core\Objects.cs" />
+    <Compile Include="Core\ObjectExtensions.cs" />
     <Compile Include="Core\PluginUtils.cs" />
     <Compile Include="Core\QuantizerHelper.cs" />
     <Compile Include="Core\RssHelper.cs" />