Index: Core/Common/src/Core.Common.Base/IObservable.cs
===================================================================
diff -u -re823dc6f52bf6a01f421c69b95a07e6258ec33de -r0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be
--- Core/Common/src/Core.Common.Base/IObservable.cs	(.../IObservable.cs)	(revision e823dc6f52bf6a01f421c69b95a07e6258ec33de)
+++ Core/Common/src/Core.Common.Base/IObservable.cs	(.../IObservable.cs)	(revision 0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be)
@@ -2,9 +2,9 @@
 {
     /// <summary>
     /// Interface that describes the methods that need to be implemented on classes that are supposed to be observable.
-    /// Observables should (asynchronously) notify their observers of the fact that their internal state has changed.
-    /// <seealso cref="IObserver"/>
+    /// Observables should notify their observers of the fact that their internal state has changed.
     /// </summary>
+    /// <seealso cref="IObserver"/>
     public interface IObservable
     {
         /// <summary>
Index: Core/Common/src/Core.Common.Base/IObserver.cs
===================================================================
diff -u -re823dc6f52bf6a01f421c69b95a07e6258ec33de -r0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be
--- Core/Common/src/Core.Common.Base/IObserver.cs	(.../IObserver.cs)	(revision e823dc6f52bf6a01f421c69b95a07e6258ec33de)
+++ Core/Common/src/Core.Common.Base/IObserver.cs	(.../IObserver.cs)	(revision 0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be)
@@ -2,8 +2,8 @@
 {
     /// <summary>
     /// Interface that describes the methods that need to be implemented on classes that are supposed to be observer.
-    /// <seealso cref="IObservable"/>
     /// </summary>
+    /// <seealso cref="IObservable"/>
     public interface IObserver
     {
         /// <summary>
Index: Core/Common/src/Core.Common.Base/Observable.cs
===================================================================
diff -u -rcf4f947febf6a8d92379094230ca4bade46a87d0 -r0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be
--- Core/Common/src/Core.Common.Base/Observable.cs	(.../Observable.cs)	(revision cf4f947febf6a8d92379094230ca4bade46a87d0)
+++ Core/Common/src/Core.Common.Base/Observable.cs	(.../Observable.cs)	(revision 0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be)
@@ -23,7 +23,8 @@
 
         public void NotifyObservers()
         {
-            // Iterate through a copy of the list of observers; an update of one observer might result in detaching another observer (which will result in a "list modified" exception over here otherwise)
+            // Iterate through a copy of the list of observers; an update of one observer might result in detaching
+            // another observer (which will result in a "list modified" exception over here otherwise)
             foreach (var observer in observers.ToArray())
             {
                 // Ensure the observer is still part of the original list of observers
Index: Core/Common/src/Core.Common.Base/Properties/Resources.Designer.cs
===================================================================
diff -u -rcf4f947febf6a8d92379094230ca4bade46a87d0 -r0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be
--- Core/Common/src/Core.Common.Base/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision cf4f947febf6a8d92379094230ca4bade46a87d0)
+++ Core/Common/src/Core.Common.Base/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be)
@@ -90,10 +90,10 @@
         /// <summary>
         ///   Looks up a localized string similar to Stap {0} van {1}  |  {2}.
         /// </summary>
-        internal static string FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1_____ProgressText_2 {
+        internal static string FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1_ProgressText_2 {
             get {
-                return ResourceManager.GetString("FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1__|__P" +
-                        "rogressText_2", resourceCulture);
+                return ResourceManager.GetString("FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1_Progr" +
+                        "essText_2", resourceCulture);
             }
         }
         
Index: Core/Common/src/Core.Common.Base/Properties/Resources.resx
===================================================================
diff -u -rcf4f947febf6a8d92379094230ca4bade46a87d0 -r0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be
--- Core/Common/src/Core.Common.Base/Properties/Resources.resx	(.../Resources.resx)	(revision cf4f947febf6a8d92379094230ca4bade46a87d0)
+++ Core/Common/src/Core.Common.Base/Properties/Resources.resx	(.../Resources.resx)	(revision 0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be)
@@ -126,7 +126,7 @@
   <data name="Activity_Finish_Execution_of_ActivityName_0_has_failed" xml:space="preserve">
     <value>Uitvoeren van '{0}' is mislukt.</value>
   </data>
-  <data name="FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1__|__ProgressText_2" xml:space="preserve">
+  <data name="FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1_ProgressText_2" xml:space="preserve">
     <value>Stap {0} van {1}  |  {2}</value>
   </data>
   <data name="Project_Constructor_Default_name" xml:space="preserve">
Index: Core/Common/src/Core.Common.Base/Service/FileImportActivity.cs
===================================================================
diff -u -r441bb5d121bef7fcc0abed7ae6021e2f062e7973 -r0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be
--- Core/Common/src/Core.Common.Base/Service/FileImportActivity.cs	(.../FileImportActivity.cs)	(revision 441bb5d121bef7fcc0abed7ae6021e2f062e7973)
+++ Core/Common/src/Core.Common.Base/Service/FileImportActivity.cs	(.../FileImportActivity.cs)	(revision 0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be)
@@ -22,26 +22,30 @@
         /// <param name="fileImporter">The <see cref="IFileImporter"/> to use for importing the data.</param>
         /// <param name="target">The target object to import the data to.</param>
         /// <param name="filePaths">The paths of the files to import the data from.</param>
-        /// <exception cref="ArgumentException">Thrown when <paramref name="fileImporter"/> is <c>null</c>.</exception>
-        /// <exception cref="ArgumentException">Thrown when <paramref name="target"/> is <c>null</c>.</exception>
-        /// <exception cref="ArgumentException">Thrown when <paramref name="filePaths"/> is <c>null</c> or contains no file paths.</exception>
+        /// <exception cref="ArgumentNullException">Thrown when any input argument is <c>null</c>.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="filePaths"/> is empty.</exception>
         public FileImportActivity(IFileImporter fileImporter, object target, string[] filePaths)
         {
             if (fileImporter == null)
             {
-                throw new ArgumentException("fileImporter");
+                throw new ArgumentNullException("fileImporter");
             }
 
             if (target == null)
             {
-                throw new ArgumentException("target");
+                throw new ArgumentNullException("target");
             }
 
-            if (filePaths == null || !filePaths.Any())
+            if (filePaths == null)
             {
-                throw new ArgumentException("files");
+                throw new ArgumentNullException("filePaths");
             }
 
+            if (!filePaths.Any())
+            {
+                throw new ArgumentException("filePaths");
+            }
+
             this.fileImporter = fileImporter;
             this.target = target;
             this.filePaths = filePaths;
@@ -81,7 +85,7 @@
 
         private void ImportFromFile(string fileName)
         {
-            fileImporter.ProgressChanged = (currentStepName, currentStep, totalSteps) => { ProgressText = string.Format(Resources.FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1_____ProgressText_2, currentStep, totalSteps, currentStepName); };
+            fileImporter.ProgressChanged = (currentStepName, currentStep, totalSteps) => { ProgressText = string.Format(Resources.FileImportActivity_ImportFromFile_Step_CurrentProgress_0_of_TotalProgress_1_ProgressText_2, currentStep, totalSteps, currentStepName); };
 
             fileImporter.Import(target, fileName);
         }
Index: Core/Common/test/Core.Common.Base.Test/Service/FileImportActivityTest.cs
===================================================================
diff -u -rf7d7a919dec1b7d79672af043f268cde57aab0ba -r0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be
--- Core/Common/test/Core.Common.Base.Test/Service/FileImportActivityTest.cs	(.../FileImportActivityTest.cs)	(revision f7d7a919dec1b7d79672af043f268cde57aab0ba)
+++ Core/Common/test/Core.Common.Base.Test/Service/FileImportActivityTest.cs	(.../FileImportActivityTest.cs)	(revision 0e7b2de6dcd8323ea6f330f7e5f5d2b062f9c1be)
@@ -11,7 +11,7 @@
     public class FileImportActivityTest
     {
         [Test]
-        [ExpectedException(typeof(ArgumentException), ExpectedMessage = "fileImporter")]
+        [ExpectedException(typeof(ArgumentNullException), ExpectedMessage = "Value cannot be null.\r\nParameter name: fileImporter")]
         public void Constructor_ImporterEqualsNull_ArgumentExceptionIsThrown()
         {
             // Setup / Call / Assert
@@ -22,7 +22,7 @@
         }
 
         [Test]
-        [ExpectedException(typeof(ArgumentException), ExpectedMessage = "target")]
+        [ExpectedException(typeof(ArgumentNullException), ExpectedMessage = "Value cannot be null.\r\nParameter name: target")]
         public void Constructor_TargetEqualsNull_ArgumentExceptionIsThrown()
         {
             // Setup
@@ -39,7 +39,7 @@
         }
 
         [Test]
-        [ExpectedException(typeof(ArgumentException), ExpectedMessage = "files")]
+        [ExpectedException(typeof(ArgumentNullException), ExpectedMessage = "Value cannot be null.\r\nParameter name: filePaths")]
         public void Constructor_FilesEqualsNull_ArgumentExceptionIsThrown()
         {
             // Setup
@@ -53,7 +53,7 @@
         }
 
         [Test]
-        [ExpectedException(typeof(ArgumentException), ExpectedMessage = "files")]
+        [ExpectedException(typeof(ArgumentException), ExpectedMessage = "filePaths")]
         public void Constructor_FilesEmpty_ArgumentExceptionIsThrown()
         {
             // Setup