Workaround: manually resize the editor or drag it upwards 

RadControls are slow when using at design time in a form containing a lot of controls, split containers and table layout panels

To reproduce:
- Add RadLayoutControl to a form.
- Change the Language property at design time.
- You will receive the following message: There is already a command handler for the menu command '1496a755-94de-11d0-8c3f-00c04fc2aae2 : 103'. 

Workaround:
- Reopen the designer.

1. Run TelerikExamplesLauncher.exe - GanttView "First Look" example
2. Scroll and select a task near the bottom, for example: "Send your engagement announcement to newspapers" under "The Guest > 6 Months +"
3. Use splitter to resize between TextView and GraphicalView

You will see that GraphicalView doesn't move but TextView loses task position and scrolls to the top.

Note that using mouse Scroll refreshes the correct position of TextView on the selected task.

To reproduce: run the sample project, open the test.rtf file and start scrolling with the mouse. As a result, you will encounter the following error:

************** Exception Text **************
System.ArgumentException: Parameter is not valid.
   at System.Drawing.Image.get_RawFormat()
   at System.Drawing.Graphics.IgnoreMetafileErrors(Image image, Int32& errorStatus)
   at System.Drawing.Graphics.DrawImage(Image image, Single x, Single y, Single width, Single height)
   at System.Drawing.Graphics.DrawImage(Image image, RectangleF rect)
   at Telerik.WinControls.RichTextEditor.UI.GDIPaintingContext.DrawImage(Image image, RectangleF rectangle, Double opacity)
   at Telerik.WinControls.RichTextEditor.UI.Image.PaintCore(IPaintingContext context)
   at Telerik.WinControls.RichTextEditor.UI.UIElement.Paint(IPaintingContext context)
   at Telerik.WinControls.RichTextEditor.UI.FrameworkElement.PaintElement(IGraphics graphics, Single angle, SizeF scale)
   at Telerik.WinControls.RadElement.DoOwnPaint(IGraphics graphics, Single angle, SizeF scale)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintOverride(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChild(RadElement child, IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.VisualElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintOverride(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChild(RadElement child, IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.VisualElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintOverride(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChild(RadElement child, IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.VisualElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintOverride(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChild(RadElement child, IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.VisualElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintOverride(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChild(RadElement child, IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.VisualElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintOverride(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChild(RadElement child, IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.VisualElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintOverride(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChild(RadElement child, IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.VisualElement.PaintChildren(IGraphics graphics, Rectangle clipRectange, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadElement.Paint(IGraphics graphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadItem.PaintOverride(IGraphics screenRadGraphics, Rectangle clipRectangle, Single angle, SizeF scale, Boolean useRelativeTransformation)
   at Telerik.WinControls.RadControl.OnPaint(PaintEventArgs e)
   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)
   at System.Windows.Forms.Control.WmPaint(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at Telerik.WinControls.RadControl.WndProc(Message& m)
   at Telerik.WinControls.UI.RadRichTextEditor.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Project Update Utility throws unhandled exception when you try to upgrade project which files are not checked-out from source control.

Workaround:

            this.radChat1.ChatElement.InputTextBox.TextBoxItem.TextBoxControl.Multiline = true;
            this.radChat1.ChatElement.InputTextBox.ButtonsStack.Children.Remove(this.radChat1.ChatElement.ShowToolbarButtonElement);
            this.radChat1.ChatElement.InputTextBox.ButtonsStack.Children.Remove(this.radChat1.ChatElement.SendButtonElement);
            StackLayoutElement stack = new StackLayoutElement();
            stack.MinSize = new Size(0, 60);
            this.radChat1.ChatElement.InputTextBox.Parent.Children.Add(stack);
            this.radChat1.ChatElement.InputTextBox.Parent.Children.Remove(this.radChat1.ChatElement.InputTextBox);
            stack.StretchHorizontally = true;
            stack.Orientation = Orientation.Horizontal;
            stack.Children.Add(this.radChat1.ChatElement.InputTextBox);
            stack.Children.Add(this.radChat1.ChatElement.ShowToolbarButtonElement);
            stack.Children.Add(this.radChat1.ChatElement.SendButtonElement);
            this.radChat1.ChatElement.ShowToolbarButtonElement.StretchHorizontally = false;
            this.radChat1.ChatElement.SendButtonElement.StretchHorizontally = false;

To reproduce: 

-Open the FileExplorer example. 

- Resize the panel (see attached).

As workaround please, rename the controls with Find & Replace from VS Editor.

Use attached to reproduce.

Workaround:

When we have start position set to center screen:

            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;

RadForm does not calculate the correct location of the form on HDPI devices.

HI,

Exploring the Demo Winforms FilterView component a bug is present.

When you expand several categories ,the automatic Vertical Scroll bar is showed but the "Maximum"  property value is wrong.

You can't see all the items inside. Some items are hidden at bottom.

But if you collapse some category the new "Maximum" values takes the right previous value before collapsing showing more space as expected

I have a workaround to prevent this situation calling CategoryExpandedChanged event.

Firstly I need to call Application.DoEvents() in order to resizing internally by the component all the StackLayoutPanels connaining the Category Items 

After that, I call the private method UpdateScrollBars (Suggested by support) and the ScrollBar takes the right size for its content.

Now I can show all the contained items inside the FilterView panel.

FRC

public partial class RadForm1 : Telerik.WinControls.UI.RadForm
    {
        public RadForm1()
        {
            InitializeComponent();
            DataTable dt = new DataTable();
            for (int i = 0; i < 20; i++)
            {
                dt.Columns.Add("col" + i, typeof(string));
            }
            for (int i = 0; i < 10; i++)
            {
                DataRow r = dt.NewRow();
                foreach (DataColumn col in dt.Columns)
                {
                    r[col.ColumnName] = Guid.NewGuid().ToString();
                }
                dt.Rows.Add(r);
            }
            this.radFilterView1.DataSource = dt;
          
        }


        private void radFilterView1_CategoryCreated(object sender, Telerik.WinControls.UI.FilterView.FilterViewCategoryCreatedEventArgs e)
        {
            e.Category.ExpandedChanged += Category_ExpandedChanged;
            e.Category.Expanded = false;

        }

        private void Category_ExpandedChanged(object? sender, EventArgs e)
        {
            // You need pass the control to Windows main loop to perform the pending telerik events after property Expanded change in order to resize internally
            // the StackLayoutPanel Containers before calling UpdateScrollBars
            Application.DoEvents();
            // Now your code
            MethodInfo mi = typeof(RadFilterViewElement).GetMethod("UpdateScrollbars", BindingFlags.Instance | BindingFlags.NonPublic);
            mi.Invoke(this.radFilterView1.FilterViewElement, new object[] { this.radFilterView1.FilterViewElement.ElementsPanel.Size });
            // Hide the horizontal scrolll bar
            radFilterView1.FilterViewElement.HorizontalScrollBar.Visibility =ElementVisibility.Collapsed;
        }

    }

Setting the SyntaxEditorElement.HorizontalScrollBar.Visibility property to Collapsed indeed hides the horizontal scrollbar but it is still measured and arranged and overlaps the view if you shrink the view: