Fix removing a control from a TableLayout before it has been initialized

src/Eto.Gtk/Forms/TableLayoutHandler.gtk3.cs

@@ -152,6 +152,9 @@ bool Attach(Control child, int x, int y)
 
 		public void Remove(Control child)
 		{
+			if (controls == null)
+				return;
+
 			for (int y = 0; y < controls.GetLength(0); y++)
 			{
 				for (int x = 0; x < controls.GetLength(1); x++)

src/Eto.Mac/Forms/TableLayoutHandler.cs

@@ -347,6 +347,8 @@ public void Move(Control child, int x, int y)
 
 		public void Remove(Control child)
 		{
+			if (views == null)
+				return;
 			for (int y = 0; y < views.GetLength(0); y++)
 				for (int x = 0; x < views.GetLength(1); x++)
 				{

src/Eto.WinForms/Forms/TableLayoutHandler.cs

@@ -272,7 +272,8 @@ public void Remove(Control child)
 			if (childControl.Parent == Control)
 			{
 				var pos = Control.GetCellPosition(childControl);
-				views[pos.Column, pos.Row] = null;
+				if (views != null)
+					views[pos.Column, pos.Row] = null;
 				childControl.Parent = null;
 				SetEmptyCell(pos.Column, pos.Row);
 			}

src/Eto.Wpf/Forms/TableLayoutHandler.cs

@@ -361,6 +361,8 @@ public Padding Padding
 
 		void Remove(int x, int y)
 		{
+			if (controls == null)
+				return;
 			var control = controls[x, y];
 			if (control != null)
 			{

src/Eto/Forms/Controls/Control.cs

@@ -991,8 +991,8 @@ internal set
 	/// </remarks>
 	public void Detach()
 	{
-		if (VisualParent != null)
-			VisualParent.Remove(this);
+		VisualParent?.Remove(this);
+		Parent?.Remove(this);
 	}
 
 	static readonly object IsAttached_Key = new object();