fix #1837

while the project is open, the menu still doesn't update to account for this, but at least it can be saved properly now

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

@@ -1317,7 +1317,7 @@ namespace BizHawk.Client.EmuHawk
 					var item = new ToolStripMenuItem($"Show Player {i}")
 					{
 						CheckOnClick = true,
-						Checked = true
+						Checked = playerMenus[i].DropDownItems.OfType<ToolStripMenuItem>().Any(mi => mi.Checked)
 					};
 
 					ToolStripMenuItem dummyObject = playerMenus[i];