apply the settings

ILSpy/App.xaml.cs

@@ -30,6 +30,7 @@ using System.Windows.Navigation;
 using System.Windows.Threading;
 
 using ICSharpCode.ILSpy.TextView;
+using ICSharpCode.ILSpy.Options;
 
 namespace ICSharpCode.ILSpy
 {
@@ -57,8 +58,9 @@ namespace ICSharpCode.ILSpy
 		public App()
 		{
 			var cmdArgs = Environment.GetCommandLineArgs().Skip(1);
+			var allowMultipleInstance = MiscSettingsInstance.Current.LoadMiscSettings().AllowMultipleInstances;
 			App.CommandLineArguments = new CommandLineArguments(cmdArgs);
-			if (App.CommandLineArguments.SingleInstance ?? true) {
+			if ((App.CommandLineArguments.SingleInstance ?? true) && (!allowMultipleInstance)) {
 				cmdArgs = cmdArgs.Select(FullyQualifyPath);
 				string message = string.Join(Environment.NewLine, cmdArgs);
 				if (SendToPreviousInstance("ILSpy:\r\n" + message, !App.CommandLineArguments.NoActivate)) {

ILSpy/Options/MiscSettingsLoader.cs

@@ -4,11 +4,24 @@ namespace ICSharpCode.ILSpy.Options
 {
 	public interface IMiscSettingsLoader
 	{
+		MiscSettings LoadMiscSettings();
 		MiscSettings LoadMiscSettings(ILSpySettings settings);
 	}
 
 	public class MiscSettingsLoader : IMiscSettingsLoader
 	{
+		private ILSpySettings settings;
+
+		public MiscSettingsLoader()
+		{
+			settings = ILSpySettings.Load();
+		}
+
+		public MiscSettings LoadMiscSettings()
+		{
+			return LoadMiscSettings(settings);
+		}
+
 		public MiscSettings LoadMiscSettings(ILSpySettings settings)
 		{
 			XElement e = settings["MiscSettings"];