To reproduce:

1. Add a RadGridView with a GridViewMultiComboBoxColumn. Enable the auto filter functionality for this column and add an appropriate FilterDescriptor to the RadMultiColumnComboBoxElement.
2. Using the keyboard arrows only (no mouse), navigate to the GridViewMultiComboBoxColumn.
3. Type "ba" by using the keyboard. The "b" is lost and only the "a" gets to the filter. I expect the filter to show "ba".

Workaround: use custom row behavior

public Form1()
{
    InitializeComponent();
    //register the custom row  behavior
    BaseGridBehavior gridBehavior = radGridView1.GridBehavior as BaseGridBehavior;
    gridBehavior.UnregisterBehavior(typeof(GridViewDataRowInfo));
    gridBehavior.RegisterBehavior(typeof(GridViewDataRowInfo), new CustomGridDataRowBehavior());
}

public class CustomGridDataRowBehavior : GridDataRowBehavior
{
    protected override bool ProcessAlphaNumericKey(KeyPressEventArgs keys)
    {
        bool result = base.ProcessAlphaNumericKey(keys);
        if (this.IsInEditMode &&
            (this.BeginEditMode == RadGridViewBeginEditMode.BeginEditOnKeystroke ||
             this.BeginEditMode == RadGridViewBeginEditMode.BeginEditOnKeystrokeOrF2))
        {
            if (this.GridViewElement.ActiveEditor is RadMultiColumnComboBoxElement)
            {
                this.GridViewElement.ActiveEditor.Value = keys.KeyChar;
                if (this.GridViewElement.IsInEditMode)
                {
                    RadMultiColumnComboBoxElement mccb = (RadMultiColumnComboBoxElement)this.GridViewElement.ActiveEditor;
                    RadTextBoxItem textBoxItem = mccb.TextBoxElement.TextBoxItem;
                    textBoxItem.Clear();
                    textBoxItem.Text =  keys.KeyChar.ToString();
                    textBoxItem.SelectionStart = 1;
                    textBoxItem.SelectionLength = 0;
                }

                return true;
            }
        }
        return result;
    }
}

To reproduce: 

CultureInfo culture = new CultureInfo("en-US");
culture.DateTimeFormat.FirstDayOfWeek = DayOfWeek.Monday;
culture.DateTimeFormat.CalendarWeekRule = CalendarWeekRule.FirstFourDayWeek;
this.radCalendar1.ShowRowHeaders = true;
this.radCalendar1.Culture = culture;

On 125% dpi:

 However, if you close the list and open it again, the list has the correct height (the gap is gone).

To reproduce:
-Set RTL via the insane:
RadMessageBox.Instance.RightToLeft = RightToLeft.Yes;

- You will notice that layout is not changed when the messagebox is shown.

Worlaround:
- Use the RadMessageBox show method with the following parameters:

RadMessageBox.Show(this, "test", "caption", MessageBoxButtons.OKCancel, icon, MessageBoxDefaultButton.Button1, RightToLeft.Yes);

To reproduce:

public Form1()
{
    InitializeComponent();

    RadMessageBox.Instance.AutoSize = true;
}

private void radButton1_Click(object sender, EventArgs e)
{
    string msg = string.Format("Test", (sender as RadButton).Name);
    RadMessageBox.Show(msg, "Error");
}

Note that the size of  RadMessageBox is adjusted automatically to display the whole content. Hence, it is not necessary to set the RadMessageBox.Instance.AutoSize property to true.

Workaround:

public class MyInputBehavior : InputBehavior
{
    public MyInputBehavior(DocumentView view)
        : base(view)
    {
  
    }
  
    public override bool ProcessKeyPress(System.Windows.Forms.KeyPressEventArgs e)
    {
        // TO DO: You code here
        e.KeyChar = char.ToUpper(e.KeyChar);
        return true;
        // By commenting the base call you are supresing the default logic
        //return base.ProcessKeyPress(e);
    }
}

Then you should replace the default input behavior by using the following code snippet:
this.richTextBox.DocumentView.InputBehavior = new MyInputBehavior(this.richTextBox.DocumentView);

Set one of the monitors to use 125% DPI scaling. Start the attached project on a monitor with 100% DPI scaling - the form is expected to be with size 400,400. Move the form to the monitor with 125% DPI scaling. You are expecting the form's size to be 500,500, but it is 507,521. Please refer to the screenshots.

Workaround:

Override the RadForm.ScaleControl method as follows:

    Protected Overrides Sub ScaleControl(factor As SizeF, specified As BoundsSpecified)
        Dim initialSize As Size = Me.Size
        MyBase.ScaleControl(factor, specified)
        Me.Size = TelerikDpiHelper.ScaleSize(initialSize, factor)
    End Sub

In this scenario, the RadMap control is placed inside a RadDocking pane. The exception is raised when you click and hold the mouse on a drawn polygon. Then the mouse is released outside of the Form. When closing the tab holding the map, an exception is thrown.

In the above image, the height of the control is not calculated correctly in the Windows 11 theme. In addition, the Details arrow button overlaps the text.

Workaround: 
((StackLayoutElement)this.radBrowseEditor1.BrowseElement.Children[2]).ShouldHandleMouseInput = false;
this.radBrowseEditor1.BrowseElement.TextBoxItem.RouteMessages = true;

To reproduce:

public Form1()
{
    InitializeComponent();
    this.radPropertyGrid1.SelectedObject = this;

    this.radPropertyGrid1.ContextMenuOpening += radPropertyGrid1_ContextMenuOpening;
}

private void radPropertyGrid1_ContextMenuOpening(object sender, Telerik.WinControls.UI.PropertyGridContextMenuOpeningEventArgs e)
{
    foreach (RadItem item in e.Menu.Items)
    {
        if (item.Text == "Sort")
        {
            item.Visibility = ElementVisibility.Collapsed;
            item.PropertyChanged += item_PropertyChanged;
        }
    }
}

Workaround:
private void radPropertyGrid1_ContextMenuOpening(object sender, Telerik.WinControls.UI.PropertyGridContextMenuOpeningEventArgs e)
{
    RadItem item = null;
    for (int i = 0; i < e.Menu.Items.Count; i++)
    {
        item = e.Menu.Items[i];
        if (item.Text=="Sort")
        {
            e.Menu.Items.Remove(item);
        }
    } 
}

Expose a way to disable the Spell Checking Complete dialog:

When RadPanel is set to AutoSize, it should update its size automatically when changing the visibility of some control inside it.

Workaround:
 public class CustomRadPanel : RadPanel
    {
        public override string ThemeClassName
        {
            get
            {
                return typeof(RadPanel).FullName;
            }
            set
            {
                base.ThemeClassName = value;
            }
        }

        protected override void OnLayout(LayoutEventArgs e)
        {
            base.OnLayout(e);
            int maxHeight = 0;
            foreach (Control control in this.Controls)
            {
                if (control.Visible)
                {
                    maxHeight = Math.Max(control.Height, maxHeight);
                }
            }
            this.AutoSize = false;
            this.Height = maxHeight;
        }
    }

To reproduce:
- Drop RadMarkupDialog on the form
- In code set its DefaultFont and show it

WORKAROUND:
Create an instance of RadMarkupDialog prior showing it, not at design time.