UI: Fixed some rare crashes when shutting down

GUI.NET/Debugger/frmMemoryViewer.cs

@@ -24,6 +24,7 @@ namespace Mesen.GUI.Debugger
 		private bool _updating = false;
 		private DateTime _lastUpdate = DateTime.MinValue;
 		private TabPage _selectedTab;
+		private bool _formClosed;
 
 		public frmMemoryViewer()
 		{
@@ -106,6 +107,13 @@ namespace Mesen.GUI.Debugger
 			ConfigManager.Config.DebugInfo.RamMemoryType = cboMemoryType.GetEnumValue<DebugMemoryType>();
 			ConfigManager.ApplyChanges();
 			DebugWorkspaceManager.SaveWorkspace();
+
+			if(this._notifListener != null) {
+				this._notifListener.Dispose();
+				this._notifListener = null;
+			}
+
+			_formClosed = true;
 		}
 
 		private void InitShortcuts()
@@ -216,6 +224,9 @@ namespace Mesen.GUI.Debugger
 				case InteropEmu.ConsoleNotificationType.GameReset:
 				case InteropEmu.ConsoleNotificationType.GameLoaded:
 					this.BeginInvoke((Action)(() => {
+						if(_formClosed) {
+							return;
+						}
 						this.InitMemoryTypeDropdown(false);
 						ctrlMemoryAccessCounters.InitMemoryTypeDropdown();
 					}));
@@ -306,6 +317,10 @@ namespace Mesen.GUI.Debugger
 
 		private void RefreshData()
 		{
+			if(_formClosed) {
+				return;
+			}
+
 			if(DebugWorkspaceManager.GetWorkspace() != this._previousWorkspace) {
 				this.InitTblMappings();
 				_previousWorkspace = DebugWorkspaceManager.GetWorkspace();

GUI.NET/Forms/frmMain.cs

@@ -52,6 +52,7 @@ namespace Mesen.GUI.Forms
 		private float _yFactor = 1;
 		private bool _enableResize = false;
 		private bool _overrideWindowSize = false;
+		private bool _shuttingDown = false;
 
 		private frmFullscreenRenderer _frmFullscreenRenderer = null;
 
@@ -241,6 +242,8 @@ namespace Mesen.GUI.Forms
 				return;
 			}
 
+			_shuttingDown = true;
+
 			//Stop menu update timer, and process all pending events before stopping the core
 			//This prevents some rare crashes on shutdown
 			menuTimer.Stop();
@@ -913,6 +916,10 @@ namespace Mesen.GUI.Forms
 
 		private void UpdateMenus()
 		{
+			if(_shuttingDown) {
+				return;
+			}
+
 			try {
 				if(this.InvokeRequired) {
 					this.BeginInvoke((MethodInvoker)(() => this.UpdateMenus()));