diff --git a/mRemoteNGTests/Tree/ExpandNodeClickHandlerTests.cs b/mRemoteNGTests/Tree/ClickHandlers/ExpandNodeClickHandlerTests.cs
similarity index 77%
rename from mRemoteNGTests/Tree/ExpandNodeClickHandlerTests.cs
rename to mRemoteNGTests/Tree/ClickHandlers/ExpandNodeClickHandlerTests.cs
index be1d74927..e4ffcb641 100644
--- a/mRemoteNGTests/Tree/ExpandNodeClickHandlerTests.cs
+++ b/mRemoteNGTests/Tree/ClickHandlers/ExpandNodeClickHandlerTests.cs
@@ -1,7 +1,7 @@
-using mRemoteNG.Connection;
+using System;
+using mRemoteNG.Connection;
 using mRemoteNG.Container;
 using mRemoteNG.Tree;
-using mRemoteNG.Tree.Root;
 using mRemoteNG.UI.Controls;
 using NSubstitute;
 using NUnit.Framework;
@@ -35,5 +35,12 @@ namespace mRemoteNGTests.Tree
             _clickHandler.Execute(new ConnectionInfo());
             _connectionTree.DidNotReceiveWithAnyArgs().ToggleExpansion(new ConnectionInfo());
         }
+
+        [Test]
+        public void ExceptionThrownOnConstructorNullArg()
+        {
+            // ReSharper disable once ObjectCreationAsStatement
+            Assert.Throws<ArgumentNullException>(() => new ExpandNodeClickHandler(null));
+        }
     }
 }
\ No newline at end of file
diff --git a/mRemoteNGTests/Tree/OpenConnectionClickHandlerTests.cs b/mRemoteNGTests/Tree/ClickHandlers/OpenConnectionClickHandlerTests.cs
similarity index 71%
rename from mRemoteNGTests/Tree/OpenConnectionClickHandlerTests.cs
rename to mRemoteNGTests/Tree/ClickHandlers/OpenConnectionClickHandlerTests.cs
index 5e0f2dcbc..5ceda527d 100644
--- a/mRemoteNGTests/Tree/OpenConnectionClickHandlerTests.cs
+++ b/mRemoteNGTests/Tree/ClickHandlers/OpenConnectionClickHandlerTests.cs
@@ -1,4 +1,5 @@
-using mRemoteNG.Connection;
+using System;
+using mRemoteNG.Connection;
 using mRemoteNG.Tree;
 using NSubstitute;
 using NUnit.Framework;
@@ -25,5 +26,12 @@ namespace mRemoteNGTests.Tree
             _clickHandler.Execute(connectionInfo);
             _connectionInitiator.Received().OpenConnection(connectionInfo);
         }
+
+        [Test]
+        public void ExceptionThrownWhenConstructorGivenNullArg()
+        {
+            // ReSharper disable once ObjectCreationAsStatement
+            Assert.Throws<ArgumentNullException>(() => new OpenConnectionClickHandler(null));
+        }
     }
 }
diff --git a/mRemoteNGTests/Tree/SwitchToConnectionClickHandlerTests.cs b/mRemoteNGTests/Tree/ClickHandlers/SwitchToConnectionClickHandlerTests.cs
similarity index 71%
rename from mRemoteNGTests/Tree/SwitchToConnectionClickHandlerTests.cs
rename to mRemoteNGTests/Tree/ClickHandlers/SwitchToConnectionClickHandlerTests.cs
index 4fd60ede5..d58bf9e9a 100644
--- a/mRemoteNGTests/Tree/SwitchToConnectionClickHandlerTests.cs
+++ b/mRemoteNGTests/Tree/ClickHandlers/SwitchToConnectionClickHandlerTests.cs
@@ -1,4 +1,5 @@
-using mRemoteNG.Connection;
+using System;
+using mRemoteNG.Connection;
 using mRemoteNG.Tree;
 using NSubstitute;
 using NUnit.Framework;
@@ -25,5 +26,12 @@ namespace mRemoteNGTests.Tree
             _clickHandler.Execute(connectionInfo);
             _connectionInitiator.Received().SwitchToOpenConnection(connectionInfo);
         }
+
+        [Test]
+        public void ExceptionThrownWhenConstructorGivenNullArg()
+        {
+            // ReSharper disable once ObjectCreationAsStatement
+            Assert.Throws<ArgumentNullException>(() => new SwitchToConnectionClickHandler(null));
+        }
     }
 }
\ No newline at end of file
diff --git a/mRemoteNGTests/Tree/PreviousSessionOpenerTests.cs b/mRemoteNGTests/Tree/PreviousSessionOpenerTests.cs
index e8d0f2e6b..372296fad 100644
--- a/mRemoteNGTests/Tree/PreviousSessionOpenerTests.cs
+++ b/mRemoteNGTests/Tree/PreviousSessionOpenerTests.cs
@@ -1,4 +1,5 @@
-using mRemoteNG.Connection;
+using System;
+using mRemoteNG.Connection;
 using mRemoteNG.Tree;
 using mRemoteNG.Tree.Root;
 using mRemoteNG.UI.Controls;
@@ -30,6 +31,13 @@ namespace mRemoteNGTests.Tree
             _connectionInitiator.ReceivedWithAnyArgs(2).OpenConnection(new ConnectionInfo());
         }
 
+        [Test]
+        public void ExceptionThrownWhenConstructorGivenNullArg()
+        {
+            // ReSharper disable once ObjectCreationAsStatement
+            Assert.Throws<ArgumentNullException>(() => new PreviousSessionOpener(null));
+        }
+
         private RootNodeInfo BuildTree()
         {
             var root = new RootNodeInfo(RootNodeType.Connection);
diff --git a/mRemoteNGTests/mRemoteNGTests.csproj b/mRemoteNGTests/mRemoteNGTests.csproj
index fdf827b63..4652c0ae3 100644
--- a/mRemoteNGTests/mRemoteNGTests.csproj
+++ b/mRemoteNGTests/mRemoteNGTests.csproj
@@ -150,12 +150,12 @@
     <Compile Include="Security\EncryptedSecureStringTests.cs" />
     <Compile Include="Security\LegacyRijndaelCryptographyProviderTests.cs" />
     <Compile Include="Tree\ConnectionTreeTests.cs" />
-    <Compile Include="Tree\ExpandNodeClickHandlerTests.cs" />
+    <Compile Include="Tree\ClickHandlers\ExpandNodeClickHandlerTests.cs" />
     <Compile Include="Tree\NodeSearcherTests.cs" />
-    <Compile Include="Tree\OpenConnectionClickHandlerTests.cs" />
+    <Compile Include="Tree\ClickHandlers\OpenConnectionClickHandlerTests.cs" />
     <Compile Include="Tree\PreviousSessionOpenerTests.cs" />
     <Compile Include="Tree\RootNodeInfoTests.cs" />
-    <Compile Include="Tree\SwitchToConnectionClickHandlerTests.cs" />
+    <Compile Include="Tree\ClickHandlers\SwitchToConnectionClickHandlerTests.cs" />
     <Compile Include="UI\Controls\TestForm.cs">
       <SubType>Form</SubType>
     </Compile>
diff --git a/mRemoteNGTests/mRemoteNGTests.csproj.DotSettings b/mRemoteNGTests/mRemoteNGTests.csproj.DotSettings
new file mode 100644
index 000000000..1b5bada58
--- /dev/null
+++ b/mRemoteNGTests/mRemoteNGTests.csproj.DotSettings
@@ -0,0 +1,2 @@
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=tree_005Cclickhandlers/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>
\ No newline at end of file
diff --git a/mRemoteV1/Tree/ClickHandlers/OpenConnectionClickHandler.cs b/mRemoteV1/Tree/ClickHandlers/OpenConnectionClickHandler.cs
index 786e70bcf..75d3f1972 100644
--- a/mRemoteV1/Tree/ClickHandlers/OpenConnectionClickHandler.cs
+++ b/mRemoteV1/Tree/ClickHandlers/OpenConnectionClickHandler.cs
@@ -1,4 +1,5 @@
-using mRemoteNG.Connection;
+using System;
+using mRemoteNG.Connection;
 
 
 namespace mRemoteNG.Tree
@@ -9,6 +10,8 @@ namespace mRemoteNG.Tree
 
         public OpenConnectionClickHandler(IConnectionInitiator connectionInitiator)
         {
+            if (connectionInitiator == null)
+                throw new ArgumentNullException(nameof(connectionInitiator));
             _connectionInitiator = connectionInitiator;
         }
 
diff --git a/mRemoteV1/Tree/ClickHandlers/SwitchToConnectionClickHandler.cs b/mRemoteV1/Tree/ClickHandlers/SwitchToConnectionClickHandler.cs
index 23ec32c04..7c950e130 100644
--- a/mRemoteV1/Tree/ClickHandlers/SwitchToConnectionClickHandler.cs
+++ b/mRemoteV1/Tree/ClickHandlers/SwitchToConnectionClickHandler.cs
@@ -1,4 +1,5 @@
-using mRemoteNG.Connection;
+using System;
+using mRemoteNG.Connection;
 
 
 namespace mRemoteNG.Tree
@@ -9,6 +10,8 @@ namespace mRemoteNG.Tree
 
         public SwitchToConnectionClickHandler(IConnectionInitiator connectionInitiator)
         {
+            if (connectionInitiator == null)
+                throw new ArgumentNullException(nameof(connectionInitiator));
             _connectionInitiator = connectionInitiator;
         }