fix bugs from aa1de1c9d2 that made tool windows undesignable

src/BizHawk.Client.EmuHawk/FormBase.cs

@@ -21,10 +21,10 @@ namespace BizHawk.Client.EmuHawk
 			set => throw new InvalidOperationException("window title can only be changed by calling " + nameof(UpdateWindowTitle) + " (which calls " + nameof(WindowTitle) + " getter)");
 		}
 
-		protected virtual string WindowTitle => WindowTitleStatic;
-
+		protected virtual string WindowTitle => WindowTitleStatic;
+
 		/// <remarks>To enforce the "static title" semantics for implementations, this getter will be called once and cached.</remarks>
-		protected virtual string WindowTitleStatic => throw new NotImplementedException("you have to implement this; the Designer prevents this from being an abstract method");
+		protected virtual string WindowTitleStatic => GetType().Name;
 
 		protected override void OnLoad(EventArgs e)
 		{

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

@@ -9,7 +9,7 @@ using BizHawk.Emulation.Common;
 
 namespace BizHawk.Client.EmuHawk
 {
-	public abstract class ToolFormBase : FormBase
+	public class ToolFormBase : FormBase
 	{
 		public ToolManager Tools { get; set; }