Fixes #5043 - View.ScrollBars now only show if they fit - Fixes View.Viewport bug

Examples/UICatalog/Scenarios/Arrangement.cs

@@ -148,13 +148,10 @@ public override void Main ()
             ShadowStyle = ShadowStyles.Transparent,
             BorderStyle = LineStyle.Double,
             TabStop = TabBehavior.TabGroup,
-            Arrangement = ViewArrangement.Movable | ViewArrangement.Overlapped
+            Arrangement = ViewArrangement.Movable | ViewArrangement.Overlapped,
+            SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Error)
         };
 
-        datePicker.SetScheme (new Scheme (new Attribute (SchemeManager.GetScheme (Schemes.Accent).Normal.Foreground.GetBrighterColor (),
-                                                         SchemeManager.GetScheme (Schemes.Accent).Normal.Background.GetBrighterColor (),
-                                                         SchemeManager.GetScheme (Schemes.Accent).Normal.Style)));
-
         TransparentView transparentView = new ()
         {
             Title = "Transparent",

Examples/UICatalog/Scenarios/PopoverMenus.cs

@@ -400,8 +400,7 @@ void CreateAction (List<MenuItem> cultures, MenuItem culture) =>
 
                                   foreach (MenuItem item in cultures)
                                   {
-                                      ((CheckBox)item.CommandView).Value =
-                                          Thread.CurrentThread.CurrentUICulture.Name == item.HelpText ? CheckState.Checked : CheckState.UnChecked;
+                                      (item.CommandView as CheckBox)?.Value = Thread.CurrentThread.CurrentUICulture.Name == item.HelpText ? CheckState.Checked : CheckState.UnChecked;
                                   }
                               };
     }

Examples/UICatalog/Scenarios/Shortcuts.cs

@@ -263,7 +263,7 @@ private void HandleOnIsRunningChanged (object? sender, EventArgs<bool> e)
             Command = Command.New
         };
 
-        _window.CommandNotBound += (o, args) =>
+        _window.CommandNotBound += (_, args) =>
                                    {
                                        if (args.Context?.Command != Command.New)
                                        {
@@ -329,13 +329,10 @@ private void HandleOnIsRunningChanged (object? sender, EventArgs<bool> e)
 
         //framedShortcut.Orientation = Orientation.Horizontal;
 
-        if (framedShortcut.Padding is { })
-        {
-            framedShortcut.Padding.Thickness = new Thickness (0, 1, 0, 0);
-            framedShortcut.Padding.Diagnostics = ViewDiagnosticFlags.Ruler;
-        }
+        framedShortcut.Padding.Thickness = new Thickness (0, 1, 0, 0);
+        framedShortcut.Padding.Diagnostics = ViewDiagnosticFlags.Ruler;
 
-        if (framedShortcut.CommandView.Margin is { })
+        if (framedShortcut.CommandView?.Margin is { })
         {
             framedShortcut.CommandView.SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Dialog);
             framedShortcut.HelpView.SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Error);
@@ -537,7 +534,7 @@ void SetCommandViewsCanFocus (bool canFocus)
             {
                 if (peer.CanFocus)
                 {
-                    peer.CommandView.CanFocus = canFocus;
+                    peer.CommandView?.CanFocus = canFocus;
                 }
             }
             focused?.SetFocus ();

Examples/UICatalog/Scenarios/TreeViewFileSystem.cs

@@ -38,25 +38,27 @@ public override void Main ()
         using IApplication app = Application.Create ();
         app.Init ();
 
-        using Window win = new ();
+        using Runnable win = new ();
         win.Title = GetName ();
-        win.Y = 1; // menu
-        win.Height = Dim.Fill ();
 
         // MenuBar
         MenuBar menu = new ();
 
-        _treeViewFiles = new TreeView<IFileSystemInfo> { X = 0, Y = Pos.Bottom (menu), Width = Dim.Percent (50), Height = Dim.Fill () };
+        _treeViewFiles = new TreeView<IFileSystemInfo>
+        {
+            Y = Pos.Bottom (menu),
+            Height = Dim.Fill (),
+        };
         _treeViewFiles.DrawLine += TreeViewFiles_DrawLine;
 
-        // Scrollbars are disabled by default (VisibilityMode.Manual)
-
         _detailsFrame = new DetailsFrame (_iconProvider)
         {
-            X = Pos.Right (_treeViewFiles), Y = Pos.Top (_treeViewFiles), Width = Dim.Fill (), Height = Dim.Fill ()
+            X = Pos.AnchorEnd (), Y = Pos.Bottom (menu), Width = 50, Height = Dim.Fill ()
         };
+        _treeViewFiles.Width = Dim.Fill (_detailsFrame);
+
+        win.Add (menu, _treeViewFiles, _detailsFrame);
 
-        win.Add (_detailsFrame);
         _treeViewFiles.Activating += TreeViewFiles_Activating;
         _treeViewFiles.KeyDown += TreeViewFiles_KeyPress;
         _treeViewFiles.SelectionChanged += TreeViewFiles_SelectionChanged;
@@ -70,8 +72,6 @@ public override void Main ()
         _miMultiSelectCheckBox = new CheckBox
         {
             Title = "_Multi Select"
-
-            //CheckedState = CheckState.Checked
         };
         _miMultiSelectCheckBox.ValueChanged += (_, _) => SetMultiSelect ();
 
@@ -140,10 +140,9 @@ public override void Main ()
                                    ]));
 
         SetNerdIcons ();
-        win.Add (menu, _treeViewFiles);
+
         _treeViewFiles.GoToFirst ();
         _treeViewFiles.Expand ();
-
         _treeViewFiles.SetFocus ();
 
         UpdateIconCheckState ();
@@ -205,20 +204,20 @@ private void SetCustomColors ()
         if (_miCustomColorsCheckBox.Value == CheckState.Checked)
         {
             _treeViewFiles.ColorGetter = m =>
-                                         {
-                                             if ((m is IDirectoryInfo && m.Attributes.HasFlag (FileAttributes.Hidden)) || (m is IFileInfo && m.Attributes.HasFlag (FileAttributes.Hidden)))
-                                             {
-                                                 return new Scheme
-                                                 {
-                                                     Focus = new Attribute (Color.BrightRed,
-                                                                            _treeViewFiles.GetAttributeForRole (VisualRole.Focus).Background),
-                                                     Normal = new Attribute (Color.BrightYellow,
-                                                                             _treeViewFiles.GetAttributeForRole (VisualRole.Normal).Background)
-                                                 };
-                                             }
-
-                                             return null;
-                                         };
+            {
+                if ((m is IDirectoryInfo && m.Attributes.HasFlag (FileAttributes.Hidden)) || (m is IFileInfo && m.Attributes.HasFlag (FileAttributes.Hidden)))
+                {
+                    return new Scheme
+                    {
+                        Focus = new Attribute (Color.BrightRed,
+                                               _treeViewFiles.GetAttributeForRole (VisualRole.Focus).Background),
+                        Normal = new Attribute (Color.BrightYellow,
+                                                _treeViewFiles.GetAttributeForRole (VisualRole.Normal).Background)
+                    };
+                }
+
+                return null;
+            };
         }
         else
         {
@@ -393,13 +392,13 @@ private void TreeViewFiles_DrawLine (object? sender, DrawTreeViewLineEventArgs<I
                 return;
 
             case { }:
-            {
-                Cell cell = e.Cells [e.IndexOfModelText];
+                {
+                    Cell cell = e.Cells [e.IndexOfModelText];
 
-                cell.Attribute = new Attribute (Color.BrightYellow, cell.Attribute!.Value.Background, cell.Attribute!.Value.Style);
+                    cell.Attribute = new Attribute (Color.BrightYellow, cell.Attribute!.Value.Background, cell.Attribute!.Value.Style);
 
-                break;
-            }
+                    break;
+                }
         }
     }
 
@@ -482,8 +481,7 @@ private class DetailsFrame : FrameView
         public DetailsFrame (FileSystemIconProvider iconProvider)
         {
             Title = "Details";
-            base.Visible = true;
-            CanFocus = true;
+            SchemeName = SchemeManager.SchemesToSchemeName (Schemes.Dialog);
             _iconProvider = iconProvider;
         }
 

Terminal.Gui/ViewBase/Adornment/AdornmentImpl.cs

@@ -43,14 +43,13 @@ public Thickness Thickness
         get;
         set
         {
-            Thickness current = field;
-            field = value;
-
-            if (current == field)
+            if (value == field)
             {
                 return;
             }
 
+            field = value;
+
             OnThicknessChanged ();
             ThicknessChanged?.Invoke (this, EventArgs.Empty);
         }

Terminal.Gui/ViewBase/Layout/DimAuto.cs

@@ -166,8 +166,7 @@ internal override int Calculate (int location, int superviewContentSize, View us
         // 2048 x 2048 supports unit testing where no App is running.
         Size screenSize = us.App?.Screen.Size ?? new Size (2048, 2048);
         int autoMin = MinimumContentDim?.GetAnchor (superviewContentSize) ?? 0;
-        int screenX4 = dimension == Dimension.Width ? screenSize.Width * 4 : screenSize.Height * 4;
-        int autoMax = MaximumContentDim?.GetAnchor (superviewContentSize) ?? screenX4;
+        int autoMax = MaximumContentDim?.GetAnchor (superviewContentSize) ?? int.MaxValue;
 
         if (Style.FastHasFlags (DimAutoStyle.Text))
         {
@@ -177,7 +176,7 @@ internal override int Calculate (int location, int superviewContentSize, View us
                 {
                     // Set BOTH width and height (by setting Size). We do this because we will be called again, next
                     // for Dimension.Height. We need to know the width to calculate the height.
-                    us.TextFormatter.ConstrainToSize = us.TextFormatter.FormatAndGetSize (new Size (int.Min (autoMax, screenX4), screenX4));
+                    us.TextFormatter.ConstrainToSize = us.TextFormatter.FormatAndGetSize (new Size (autoMax, int.MaxValue));
                 }
 
                 textSize = us.TextFormatter.ConstrainToWidth ?? 0;
@@ -187,18 +186,18 @@ internal override int Calculate (int location, int superviewContentSize, View us
                 // For height, we need to make sure width has been calculated.
                 if (us.TextFormatter.ConstrainToHeight is null)
                 {
-                    int width = int.Min (MaximumContentDim?.GetAnchor (superviewContentSize) ?? screenX4, screenSize.Width * 4);
+                    int width = int.Min (MaximumContentDim?.GetAnchor (superviewContentSize) ?? int.MaxValue, screenSize.Width * 4);
 
                     if (us.TextFormatter.ConstrainToWidth is null)
                     {
                         // Use Viewport.Width if available; fall back to the max-based width when
                         // the view hasn't been laid out yet (Viewport.Width == 0) to avoid
                         // constraining the text to zero width which produces height = 0.
                         int constrainWidth = us.Viewport.Width > 0 ? us.Viewport.Width : width;
-                        width = us.TextFormatter.FormatAndGetSize (new Size (constrainWidth, screenX4)).Width;
+                        width = us.TextFormatter.FormatAndGetSize (new Size (constrainWidth, int.MaxValue)).Width;
                     }
 
-                    textSize = us.TextFormatter.FormatAndGetSize (new Size (us.TextFormatter.ConstrainToWidth ?? width, screenX4)).Height;
+                    textSize = us.TextFormatter.FormatAndGetSize (new Size (us.TextFormatter.ConstrainToWidth ?? width, int.MaxValue)).Height;
                     us.TextFormatter.ConstrainToHeight = textSize;
                 }
                 else
@@ -248,8 +247,8 @@ internal override int Calculate (int location, int superviewContentSize, View us
                 foreach (View v in categories.Centered)
                 {
                     maxCentered = dimension == Dimension.Width
-                                      ? v.X.GetAnchor (0) + v.Width.Calculate (0, screenX4, v, dimension)
-                                      : v.Y.GetAnchor (0) + v.Height.Calculate (0, screenX4, v, dimension);
+                                      ? v.X.GetAnchor (0) + v.Width.Calculate (0, int.MaxValue, v, dimension)
+                                      : v.Y.GetAnchor (0) + v.Height.Calculate (0, int.MaxValue, v, dimension);
                 }
 
                 maxCalculatedSize = int.Max (maxCalculatedSize, maxCentered);
@@ -272,8 +271,8 @@ internal override int Calculate (int location, int superviewContentSize, View us
                 {
                     // Need to set the relative layout for PosAnchorEnd subviews to calculate the size
                     anchoredSubView.SetRelativeLayout (dimension == Dimension.Width
-                                                           ? new Size (maxCalculatedSize, screenX4)
-                                                           : new Size (screenX4, maxCalculatedSize));
+                                                           ? new Size (maxCalculatedSize, int.MaxValue)
+                                                           : new Size (int.MaxValue, maxCalculatedSize));
 
                     maxAnchorEnd = dimension == Dimension.Width
                                        ? anchoredSubView.X.GetAnchor (maxCalculatedSize + anchoredSubView.Frame.Width)

Terminal.Gui/ViewBase/View.Content.cs

@@ -523,9 +523,12 @@ private void SetViewport (Rectangle viewport)
 
         Size newSize = new (viewport.Size.Width + thickness.Horizontal, viewport.Size.Height + thickness.Vertical);
 
-        if (newSize == Frame.Size)
+        // Detect the "adornments consume entire viewport" no-op: when the requested viewport size equals
+        // the current Viewport size (which may already be clamped to zero when Frame is smaller than adornments).
+        // In this case updating Frame would incorrectly grow it, so treat it as a no-op.
+        if (newSize == Frame.Size || viewport.Size == Viewport.Size)
         {
-            // The change is not changing the Frame, so we don't need to update it.
+            // The change is not changing the Frame, or the adornments consume the entire Frame, so we don't need to update it.
             // Just call SetNeedsLayout to update the layout.
             if (_viewportLocation != viewport.Location)
             {

Terminal.Gui/ViewBase/View.Drawing.Scheme.cs

@@ -147,6 +147,19 @@ Scheme DefaultAction ()
 
             if (SchemeManager.TryGetScheme (SchemeName, out Scheme? namedScheme))
             {
+                if (SchemeName != "Accent")
+                {
+                    return namedScheme;
+                }
+
+                // If the "Accent" scheme is requested but the theme's definition has no normal background color,
+                // derive it from the base scheme to ensure it has a valid background.
+                // There may be cases where a Theme defines an Accent like this; that should be a rare case.
+                if (namedScheme.Normal.Background == Color.None)
+                {
+                    return SchemeManager.TryGetScheme ("Base", out Scheme? baseScheme) ? Scheme.DeriveAccent (baseScheme, Driver?.DefaultAttribute) : namedScheme;
+                }
+
                 return namedScheme;
             }
 

Terminal.Gui/ViewBase/View.ScrollBars.cs

@@ -144,6 +144,21 @@ private void ConfigureVerticalScrollBarEvents (ScrollBar scrollBar)
                                       Viewport = Viewport with { Y = Math.Min (args.NewValue, scrollBar.ScrollableContentSize - scrollBar.VisibleContentSize) };
                                   };
 
+        scrollBar.VisibleChanging += (_, args) =>
+                                     {
+                                         if (!args.NewValue)
+                                         {
+                                             return;
+                                         }
+                                         int width = Frame.Size.Width - GetAdornmentsThickness ().Horizontal;
+
+                                         if (width < 1 || Viewport.Height < 2)
+                                         {
+                                             // Prevent scrollbar from becoming visible if it would cause negative available space for content
+                                             args.Cancel = true;
+                                         }
+                                     };
+
         scrollBar.VisibleChanged += (_, _) =>
                                     {
                                         // Reset scrolling
@@ -166,6 +181,21 @@ private void ConfigureHorizontalScrollBarEvents (ScrollBar scrollBar)
                                       Viewport = Viewport with { X = Math.Min (args.NewValue, scrollBar.ScrollableContentSize - scrollBar.VisibleContentSize) };
                                   };
 
+        scrollBar.VisibleChanging += (_, args) =>
+                                     {
+                                         if (!args.NewValue)
+                                         {
+                                             return;
+                                         }
+                                         int height = Frame.Size.Height - GetAdornmentsThickness ().Vertical;
+
+                                         if (Viewport.Width < 2 || height < 1)
+                                         {
+                                             // Prevent scrollbar from becoming visible if it would cause negative available space for content
+                                             args.Cancel = true;
+                                         }
+                                     };
+
         scrollBar.VisibleChanged += (_, _) =>
                                     {
                                         // Reset scrolling

Terminal.Gui/Views/DropDownList.cs

@@ -200,6 +200,19 @@ public override void EndInit ()
         base.EndInit ();
     }
 
+    /// <inheritdoc/>
+    protected override bool OnMouseEvent (Mouse ev)
+    {
+        if (!ReadOnly || !ev.Flags.FastHasFlags (MouseFlags.LeftButtonPressed))
+        {
+            return base.OnMouseEvent (ev);
+        }
+
+        App?.Popovers?.Register (_listPopover);
+
+        return InvokeCommand (Command.Activate) is true;
+    }
+
     /// <inheritdoc/>
     protected override bool OnHasFocusChanging (bool currentHasFocus, bool newHasFocus, View? currentFocused, View? newFocused)
     {
@@ -304,18 +317,18 @@ protected override bool OnGettingAttributeForRole (in VisualRole role, ref Attri
             case VisualRole.ReadOnly when ReadOnly:
 
             case VisualRole.Active when ReadOnly:
-                {
-                    currentAttribute = GetAttributeForRole (HasFocus ? VisualRole.Focus : VisualRole.Normal);
+            {
+                currentAttribute = GetAttributeForRole (HasFocus ? VisualRole.Focus : VisualRole.Normal);
 
-                    return true;
-                }
+                return true;
+            }
 
             case VisualRole.Editable when ReadOnly:
-                {
-                    currentAttribute = GetAttributeForRole (HasFocus ? VisualRole.Focus : VisualRole.Normal);
+            {
+                currentAttribute = GetAttributeForRole (HasFocus ? VisualRole.Focus : VisualRole.Normal);
 
-                    break;
-                }
+                break;
+            }
         }
 
         return false;

Terminal.Gui/Views/Menu/MenuBar.cs

@@ -309,7 +309,7 @@ public bool EnableForDesign<TContext> (ref TContext targetView) where TContext :
                                                           ]) { Id = "Preferences" }
                                   },
                                   new Line (),
-                                  new MenuItem { TargetView = targetView as View, Key = Application.GetDefaultKey (Command.Quit), Command = Command.Quit }
+                                  new MenuItem { TargetView = targetView as View, Command = Command.Quit }
                               ]));
 
         Add (new MenuBarItem ("_Edit",