TAStudio - don't draw unless Tastudio is "engaged", fixes a lot of NREs through various core reboot scenarios

src/BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.ListView.cs

@@ -155,6 +155,11 @@ namespace BizHawk.Client.EmuHawk
 
 		private void TasView_QueryItemIcon(int index, RollColumn column, ref Bitmap bitmap, ref int offsetX, ref int offsetY)
 		{
+			if (!_engaged)
+			{
+				return;
+			}
+
 			var overrideIcon = QueryItemIconCallback?.Invoke(index, column.Name);
 
 			if (overrideIcon != null)
@@ -218,6 +223,11 @@ namespace BizHawk.Client.EmuHawk
 
 		private void TasView_QueryItemBkColor(int index, RollColumn column, ref Color color)
 		{
+			if (!_engaged)
+			{
+				return;
+			}
+
 			Color? overrideColor = QueryItemBgColorCallback?.Invoke(index, column.Name);
 
 			if (overrideColor.HasValue)
@@ -260,6 +270,11 @@ namespace BizHawk.Client.EmuHawk
 
 		private void TasView_QueryRowBkColor(int index, ref Color color)
 		{
+			if (!_engaged)
+			{
+				return;
+			}
+
 			var record = CurrentTasMovie[index];
 
 			if (MainForm.IsSeeking && MainForm.PauseOnFrame == index)
@@ -299,6 +314,12 @@ namespace BizHawk.Client.EmuHawk
 
 		private void TasView_QueryItemText(int index, RollColumn column, out string text, ref int offsetX, ref int offsetY)
 		{
+			if (!_engaged)
+			{
+				text = "";
+				return;
+			}
+
 			var overrideText = QueryItemTextCallback?.Invoke(index, column.Name);
 			if (overrideText != null)
 			{

src/BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.cs

@@ -33,6 +33,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private bool _initialized;
 		private bool _exiting;
+		private bool _engaged;
 
 		private bool CanAutoload => Settings.RecentTas.AutoLoad && !string.IsNullOrEmpty(Settings.RecentTas.MostRecent);
 
@@ -109,7 +110,6 @@ namespace BizHawk.Client.EmuHawk
 				recentMacrosToolStripMenuItem.Image = Properties.Resources.Recent;
 				TASEditorManualOnlineMenuItem.Image = Properties.Resources.Help;
 				ForumThreadMenuItem.Image = Properties.Resources.TAStudio;
-
 				Icon = Properties.Resources.TAStudio_MultiSize;
 			}
 
@@ -210,6 +210,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private bool Engage()
 		{
+			_engaged = false;
 			MainForm.PauseOnFrame = null;
 			MainForm.PauseEmulator();
 
@@ -283,6 +284,7 @@ namespace BizHawk.Client.EmuHawk
 			SetSplicer();
 			SetupBoolPatterns();
 
+			_engaged = true;
 			return true;
 		}
 
@@ -790,6 +792,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private void Disengage()
 		{
+			_engaged = false;
 			MainForm.PauseOnFrame = null;
 			MainForm.AddOnScreenMessage("TAStudio disengaged");
 			MainForm.TakeBackControl();