diff --git a/ElectronNET.API/App.cs b/ElectronNET.API/App.cs
index e133c5c..793bb2a 100644
--- a/ElectronNET.API/App.cs
+++ b/ElectronNET.API/App.cs
@@ -539,9 +539,9 @@ namespace ElectronNET.API
         public Task<string> GetNameAsync() => BridgeConnector.OnResult<string>("appGetName", "appGetNameCompleted");
 
 
-        internal App() 
+        private App() 
         {
-            CommandLine = new CommandLine();
+            CommandLine = CommandLine.Instance;
         }
 
         internal static App Instance
diff --git a/ElectronNET.API/CommandLine.cs b/ElectronNET.API/CommandLine.cs
index 26a116c..40c48e4 100644
--- a/ElectronNET.API/CommandLine.cs
+++ b/ElectronNET.API/CommandLine.cs
@@ -8,7 +8,7 @@ namespace ElectronNET.API
     /// </summary>
     public sealed class CommandLine
     {
-        internal CommandLine() { }
+        private CommandLine() { }
 
         internal static CommandLine Instance
         {
diff --git a/ElectronNET.API/Entities/TitleBarStyle.cs b/ElectronNET.API/Entities/TitleBarStyle.cs
index 8fb108e..5ee48bc 100644
--- a/ElectronNET.API/Entities/TitleBarStyle.cs
+++ b/ElectronNET.API/Entities/TitleBarStyle.cs
@@ -28,4 +28,10 @@ namespace ElectronNET.API.Entities
         /// </summary>
         customButtonsOnHover
     }
+
+    public class TitleBarOverlayConfig
+    {
+        public string Color { get; set; }
+        public string SymbolColor { get; set; }
+    }
 }
\ No newline at end of file
diff --git a/ElectronNET.API/Entities/WebPreferences.cs b/ElectronNET.API/Entities/WebPreferences.cs
index f236247..ea4a1f1 100644
--- a/ElectronNET.API/Entities/WebPreferences.cs
+++ b/ElectronNET.API/Entities/WebPreferences.cs
@@ -171,6 +171,12 @@ namespace ElectronNET.API.Entities
         /// </summary>
         public bool Offscreen { get; set; }
 
+        /// <summary>
+        /// Whether to enable built-in spellcheck
+        /// </summary>
+        [DefaultValue(true)]
+        public bool Spellcheck { get; set; } = true;
+
         /// <summary>
         /// Whether to run Electron APIs and the specified preload script in a separate
         /// JavaScript context. Defaults to false. The context that the preload script runs
diff --git a/ElectronNET.Host/main.js b/ElectronNET.Host/main.js
index 201d534..c1fbd73 100644
--- a/ElectronNET.Host/main.js
+++ b/ElectronNET.Host/main.js
@@ -54,6 +54,7 @@ app.on('before-quit-for-update', () => {
 });
 
 const manifestJsonFile = require(manifestJsonFilePath);
+
 if (manifestJsonFile.singleInstance || manifestJsonFile.aspCoreBackendPort) {
     const mainInstance = app.requestSingleInstanceLock();
     app.on('second-instance', (events, args = []) => {
@@ -81,6 +82,14 @@ if (manifestJsonFile.singleInstance || manifestJsonFile.aspCoreBackendPort) {
     }
 }
 
+//Some flags need to be set before app is ready
+if (manifestJsonFile.hasOwnProperty('cliFlags') && manifesJsonFile.cliFlags.length > 0) {
+    manifestJsonFile.cliFlags.forEach(flag => {
+        app.commandLine.appendSwitch(flag);
+    });
+}
+
+
 app.on('ready', () => {
 
     // Fix ERR_UNKNOWN_URL_SCHEME using file protocol