Fixes 2094. View does not clear it's background.

Terminal.Gui/Core/View.cs

@@ -14,6 +14,7 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
+using System.Reflection;
 using NStack;
 
 namespace Terminal.Gui {
@@ -1495,16 +1496,19 @@ public virtual void Redraw (Rect bounds)
 
 			var clipRect = new Rect (Point.Empty, frame.Size);
 
-			//if (ColorScheme != null && !(this is Toplevel)) {
 			if (ColorScheme != null) {
 				Driver.SetAttribute (HasFocus ? ColorScheme.Focus : ColorScheme.Normal);
 			}
 
 			if (Border != null) {
 				Border.DrawContent (this);
+			} else if ((GetType ().IsPublic || GetType ().IsNestedPublic) && !IsOverridden (this, "Redraw") &&
+				(!NeedDisplay.IsEmpty || ChildNeedsDisplay || LayoutNeeded)) {
+
+				Clear (ViewToScreen (bounds));
 			}
 
-			if (!ustring.IsNullOrEmpty (TextFormatter.Text) || (this is Label && !AutoSize)) {
+			if (!ustring.IsNullOrEmpty (TextFormatter.Text)) {
 				Clear ();
 				// Draw any Text
 				if (TextFormatter != null) {
@@ -3050,5 +3054,19 @@ public View GetTopSuperView ()
 
 			return top;
 		}
+
+		/// <summary>
+		/// Check if the <paramref name="method"/> is overridden in the <paramref name="view"/>.
+		/// </summary>
+		/// <param name="view">The view.</param>
+		/// <param name="method">The method name.</param>
+		/// <returns><see langword="true"/> if it's overridden, <see langword="false"/>otherwise.</returns>
+		public bool IsOverridden (View view, string method)
+		{
+			Type t = view.GetType ();
+			MethodInfo m = t.GetMethod (method);
+
+			return (m.DeclaringType == t || m.ReflectedType == t) && m.GetBaseDefinition ().DeclaringType == typeof (Responder);
+		}
 	}
 }

Terminal.Gui/Views/ScrollView.cs

@@ -13,7 +13,6 @@
 
 using System;
 using System.Linq;
-using System.Reflection;
 
 namespace Terminal.Gui {
 	/// <summary>
@@ -217,7 +216,7 @@ public bool KeepContentAlwaysInViewport {
 		/// <param name="view">The view to add to the scrollview.</param>
 		public override void Add (View view)
 		{
-			if (!IsOverridden (view)) {
+			if (!IsOverridden (view, "MouseEvent")) {
 				view.MouseEnter += View_MouseEnter;
 				view.MouseLeave += View_MouseLeave;
 			}
@@ -237,14 +236,6 @@ void View_MouseEnter (MouseEventArgs e)
 			Application.GrabMouse (this);
 		}
 
-		bool IsOverridden (View view)
-		{
-			Type t = view.GetType ();
-			MethodInfo m = t.GetMethod ("MouseEvent");
-
-			return (m.DeclaringType == t || m.ReflectedType == t) && m.GetBaseDefinition ().DeclaringType == typeof (Responder);
-		}
-
 		/// <summary>
 		/// Gets or sets the visibility for the horizontal scroll indicator.
 		/// </summary>
@@ -515,7 +506,7 @@ public override bool MouseEvent (MouseEvent me)
 				vertical.MouseEvent (me);
 			} else if (me.Y == horizontal.Frame.Y && ShowHorizontalScrollIndicator) {
 				horizontal.MouseEvent (me);
-			} else if (IsOverridden (me.View)) {
+			} else if (IsOverridden (me.View, "MouseEvent")) {
 				Application.UngrabMouse ();
 			}
 			return true;

UnitTests/ViewTests.cs

@@ -2123,6 +2123,28 @@ public void DrawFrame_With_Positive_Positions ()
 			Assert.Equal (new Rect (0, 0, 8, 4), pos);
 		}
 
+		[Fact, AutoInitShutdown]
+		public void DrawFrame_With_Minimum_Size ()
+		{
+			var view = new View (new Rect (0, 0, 2, 2));
+
+			view.DrawContent += (_) => view.DrawFrame (view.Bounds, 0, true);
+
+			Assert.Equal (Point.Empty, new Point (view.Frame.X, view.Frame.Y));
+			Assert.Equal (new Size (2, 2), new Size (view.Frame.Width, view.Frame.Height));
+
+			Application.Top.Add (view);
+			Application.Begin (Application.Top);
+
+			var expected = @"
+┌┐
+└┘
+";
+
+			var pos = GraphViewTests.AssertDriverContentsWithFrameAre (expected, output);
+			Assert.Equal (new Rect (0, 0, 2, 2), pos);
+		}
+
 		[Fact, AutoInitShutdown]
 		public void DrawFrame_With_Negative_Positions ()
 		{
@@ -2452,7 +2474,7 @@ public void Clear_Can_Use_Driver_AddRune_Or_AddStr_Methods ()
 				Width = Dim.Fill (),
 				Height = Dim.Fill ()
 			};
-			view.LayoutComplete += e => {
+			view.DrawContent += e => {
 				view.DrawFrame (view.Bounds);
 				var savedClip = Application.Driver.Clip;
 				Application.Driver.Clip = new Rect (1, 1, view.Bounds.Width - 2, view.Bounds.Height - 2);
@@ -2500,7 +2522,7 @@ public void Clear_Bounds_Can_Use_Driver_AddRune_Or_AddStr_Methods ()
 				Width = Dim.Fill (),
 				Height = Dim.Fill ()
 			};
-			view.LayoutComplete += e => {
+			view.DrawContent += e => {
 				view.DrawFrame (view.Bounds);
 				var savedClip = Application.Driver.Clip;
 				Application.Driver.Clip = new Rect (1, 1, view.Bounds.Width - 2, view.Bounds.Height - 2);