Index: Core/Common/src/Core.Common.Gui/Converters/KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttribute.cs
===================================================================
diff -u -r1ccc9e6a5966ece15014631f831604eb6058dc2c -rcf9306f3121c83f6ea21fed815245481771ada1b
--- Core/Common/src/Core.Common.Gui/Converters/KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttribute.cs	(.../KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttribute.cs)	(revision 1ccc9e6a5966ece15014631f831604eb6058dc2c)
+++ Core/Common/src/Core.Common.Gui/Converters/KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttribute.cs	(.../KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttribute.cs)	(revision cf9306f3121c83f6ea21fed815245481771ada1b)
@@ -65,7 +65,7 @@
             object unit = unitPropertyInfo.GetValue(source, new object[0]);
             if (unit == null)
             {
-                throw new ArgumentNullException(nameof(unit));
+                throw new ArgumentException($"Unit property '{unitPropertyName}' was not of type string.");
             }
 
             return $"{Convert.ToString(namePropertyInfo.GetValue(source, new object[0]))} [{Convert.ToString(unit)}]";
Index: Core/Common/test/Core.Common.Gui.Test/Converters/KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttributeTest.cs
===================================================================
diff -u -r8bf7f7da2ce10b6eff2263b4c0c348ba06a9e6f1 -rcf9306f3121c83f6ea21fed815245481771ada1b
--- Core/Common/test/Core.Common.Gui.Test/Converters/KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttributeTest.cs	(.../KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttributeTest.cs)	(revision 8bf7f7da2ce10b6eff2263b4c0c348ba06a9e6f1)
+++ Core/Common/test/Core.Common.Gui.Test/Converters/KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttributeTest.cs	(.../KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttributeTest.cs)	(revision cf9306f3121c83f6ea21fed815245481771ada1b)
@@ -82,7 +82,7 @@
         }
 
         [Test]
-        public void GetName_ValidProperties_ReturnsExpectedValu()
+        public void GetName_ValidProperties_ReturnsExpectedValue()
         {
             // Setup
             const string expectedName = "expectedName";
@@ -134,7 +134,27 @@
             const string expectedMessage = "Unit property 'IDoNotExist' was not found on type TestObject.";
             TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentException>(Call, expectedMessage);
         }
+        
+        [Test]
+        public void GetName_UnitNull_ThrowsArgumentException()
+        {
+            // Setup
+            var attribute = new KeyValueAsRoundedDoubleWithoutTrailingZeroesElementAttribute(nameof(TestObject.Name),
+                                                                                             nameof(TestObject.Unit),
+                                                                                             nameof(TestObject.Value));
 
+            // Call
+            void Call() =>
+                attribute.GetName(new TestObject
+                {
+                    Unit = null
+                });
+
+            // Assert
+            const string expectedMessage = "Unit property 'Unit' was not of type string.";
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentException>(Call, expectedMessage);
+        }
+
         [Test]
         [SetCulture("nl-NL")]
         public void GetValue_WithObjectWithRoundedDoubleProperty_ReturnsValueOfProperty()