Workaround:

After updating the binding source reset the data source of the tree

this.radTreeView.DataSource = null;

this.radTreeView.DataSource = this.MyBindingSource;

Workaround:  add RadTreeNodes at run time.

To reproduce:

public Form1()
{
    InitializeComponent();

    for (int i = 0; i < 20; i++)
    {
        this.radTreeView1.Nodes.Add("Node"+i);
    }
    this.radTreeView1.AllowEdit = true;
}

The attached gif file illustrates the steps.

Workaround:
 this.radTreeView1.VScrollBar.ValueChanged+=VScrollBar_ValueChanged;
private void VScrollBar_ValueChanged(object sender, EventArgs e)
{
    this.radTreeView1.EndEdit();
}

To reproduce:

public Form1()
{
    InitializeComponent();

    this.radTreeView1.AllowDragDrop = true;
    this.radTreeView2.AllowDragDrop = true;
    for (int i = 0; i < 5; i++)
    {
        this.radTreeView1.Nodes.Add("Node1." + i);
        this.radTreeView2.Nodes.Add("Node2." + i);
    }
    this.radTreeView1.ScreenTipNeeded += radTreeView1_ScreenTipNeeded;
    this.radTreeView2.ScreenTipNeeded += radTreeView1_ScreenTipNeeded;
}

RadOffice2007ScreenTipElement _screenTip = new RadOffice2007ScreenTipElement();

private void radTreeView1_ScreenTipNeeded(object sender, Telerik.WinControls.ScreenTipNeededEventArgs e)
{
    _screenTip.CaptionLabel.Text = "Caption";
    _screenTip.MainTextLabel.Text = "text";
    _screenTip.AutoSize = true;
    e.Delay = 2000;
    e.Item.ScreenTip = _screenTip;
}

Steps:
1. Drag a node from the first RadTreeView to the other while the screen-tip is shown for the dragged node.
2. When the screen-tip is about to be hidden, the error occurs.

Workaround:

private void radTreeView1_DragStarting(object sender, RadTreeViewDragCancelEventArgs e)
{
    if (_screenTip.IsElementVisible)
    {
        this.radTreeView1.Behavior.HideScreenTip();
    }
   
}

To reproduce: use the following code:

public Form1()
{
    InitializeComponent();

    this.radTreeView1.MultiSelect = true;
    for (int i = 0; i < 3; i++)
    {
        RadTreeNode node = new RadTreeNode();
        node.Text = "Node." + i;
        for (int j = 0; j < 3; j++)
        {
            node.Nodes.Add(new RadTreeNode("Node." + i + "." + j));
        }
        this.radTreeView1.Nodes.Add(node);
    }
    this.radTreeView1.SelectedNodeChanged += radTreeView1_SelectedNodeChanged;
}

private void radTreeView1_SelectedNodeChanged(object sender, Telerik.WinControls.UI.RadTreeViewEventArgs e)
{
    Console.WriteLine(e.Node.Text + ">> Selected: " + e.Node.Selected);
}

1.Select a node
2.Press Ctrl and click over the selected node again in order to unselect it. The SelectedNodeChanged event will not fire.

Workaround:

public class MyRadTreeNode : RadTreeNode
{
    public MyRadTreeNode(string text) : base(text)
    {
    }
    
    private static readonly MethodInfo OnSelectedNodeChangedMethodInfo =
        typeof(RadTreeViewElement).GetMethod("OnSelectedNodeChanged",
            BindingFlags.NonPublic | BindingFlags.Instance, null,
            new Type[] { typeof(RadTreeNode), typeof(RadTreeViewAction) }, null);

    protected override void OnNotifyPropertyChanged(PropertyChangedEventArgs args)
    {
        base.OnNotifyPropertyChanged(args);

        if (args.PropertyName == "Selected" && TreeViewElement != null)
        {
            OnSelectedNodeChangedMethodInfo.Invoke(TreeViewElement, new object[] { this, RadTreeViewAction.ByMouse });
        }
    }
}

Error: "Object of type 'Telerik.WinControls.Enumerations.ToggleState' cannot be converted to type 'System.Boolean'."

To reproduce:

public Form1()
{
    InitializeComponent();

    List<Parent> dataItems = new List<Parent>();
    Parent currentParent;
    Child currentChild;
    List<Child> children;
    string parentId = string.Empty;
    string childId = string.Empty;
    for (int i = 1; i <= 5; i++)
    {
        parentId = Guid.NewGuid().ToString();

        children = new List<Child>();
        for (int j = 1; j < 5; j++)
        {
            childId = Guid.NewGuid().ToString();
            currentChild = new Child(childId, parentId, "SubNode." + i + "." + j, j % 2 == 0);
            children.Add(currentChild);
        }
        currentParent = new Parent(parentId, "Node." + i, i % 2 == 0,children);
        dataItems.Add(currentParent);
    }

    radTreeView1.DataSource = dataItems;
    radTreeView1.DisplayMember = "Title\\Name";
    radTreeView1.ChildMember = "Parent\\Children";
    radTreeView1.CheckedMember = "IsActive\\Status";
    radTreeView1.CheckBoxes = true;
}

public class Parent 
{
    public string ParentId { get; set; }

    public string Title { get; set; }

    public bool IsActive { get; set; }

    public List<Child> Children { get; set; }

    public Parent(string parentId, string title, bool isActive, List<Child> children)
    {
        this.ParentId = parentId;
        this.Title = title;
        this.IsActive = isActive;
        this.Children = children;
    }
}

public class Child
{
    public string ChildId { get; set; }

    public string ParentId { get; set; }

    public string Name { get; set; }

    public bool Status { get; set; }

    public Child(string childId, string parentId, string name, bool status)
    {
        this.ChildId = childId;
        this.ParentId = parentId;
        this.Name = name;
        this.Status = status;
    }
}

Workaround: Use a custom TypeConverter for the boolean properties:

public class ToggleStateConverter : TypeConverter
{
    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        return destinationType == typeof(ToggleState);
    }

    public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
    {
        if (value is bool)
        {
            switch ((bool)value)
            {
                case true:
                    return ToggleState.On;
                case false:
                    return ToggleState.Off;
                default :
                    return ToggleState.Indeterminate;
            }
        }
        return base.ConvertTo(context, culture, value, destinationType);
    }

    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        return sourceType == typeof(ToggleState);
    }

    public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
    {
        ToggleState state = (ToggleState)value;

        switch (state)
        {
            case ToggleState.On:
                return true;
            case ToggleState.Off:
                return false;
            case ToggleState.Indeterminate:
                return false;
        }

        return base.ConvertFrom(context, culture, value);
    }
}

To reproduce: 
1. Drag and drop RadTreeView on the form. 
2. Set the Dock property to true
3. Add 3 or more nodes with long names 
4. Resize the form to minimum size and you will notice that the spacing between characters is changed. 

Workaround: 
If FontSize of nodes is bigger than 13, you can subscribe to the NodeFormatting event and set the AutoEllipsis property to false: 
Font font = new Font("Segoe UI", 13f, FontStyle.Regular);
void radTreeView1_NodeFormatting(object sender, Telerik.WinControls.UI.TreeNodeFormattingEventArgs e)
{
    e.NodeElement.ContentElement.Font = font;
    e.NodeElement.ContentElement.AutoEllipsis = false;
}

If font size is smaller, you need to set the MinSize property too: 
Font font = new Font("Segoe UI", 12f, FontStyle.Regular);
void radTreeView1_NodeFormatting(object sender, Telerik.WinControls.UI.TreeNodeFormattingEventArgs e)
{
    e.NodeElement.ContentElement.Font = font;     
    e.NodeElement.ContentElement.MinSize = new System.Drawing.Size(500, 18);
}

Currently we do not support binding to the ToggleState.Indeterminate state automatically because it would require a change in the behavior of the Checked property. If you use the CheckedMember, the ToggleState.Indeterminate state is represent like ToggleState.On. 

Workaround: 
Subscribe to the NodeFormatting and NodeCheckedChanged events: 
void radTreeView1_NodeFormatting(object sender, Telerik.WinControls.UI.TreeNodeFormattingEventArgs e)
{
    Child child = e.Node.DataBoundItem as Child;
    if (child != null)
    {
        e.Node.CheckState = child.Status;
    }
}

void radTreeView1_NodeCheckedChanged(object sender, Telerik.WinControls.UI.TreeNodeCheckedEventArgs e)
{
    Child child = e.Node.DataBoundItem as Child;
    if (child != null)
    {
        child.Status = e.Node.CheckState;
    }
}

To reproduce: use the following code snippet and perform the illustrated steps on the attached gif file:

public Form1()
{
    InitializeComponent();

    for (int i = 0; i < 5; i++)
    {
        this.radTreeView1.Nodes.Add("Node" + i);
    }

    this.radTreeView1.NodeRemoving += radTreeView1_NodeRemoving;

    this.radTreeView1.AllowRemove = true;
    this.radTreeView1.AllowDefaultContextMenu = true;
}

private void radTreeView1_NodeRemoving(object sender, Telerik.WinControls.UI.RadTreeViewCancelEventArgs e)
{
    DialogResult result = RadMessageBox.Show(String.Format("Do you really want to remove the node '{0}'?", e.Node.Text),
        "Question", System.Windows.Forms.MessageBoxButtons.YesNo, RadMessageIcon.Question);

    if (result != System.Windows.Forms.DialogResult.Yes)
    {
        e.Cancel = true;
    }
}

To reproduce:
Bind the tree to the following structure:
public class DeskSites
{
    public string DeskSiteName { get; set; }

    public Channels channels { get; set; }
}

public class Channels : List<Channel>
{
    
}

public class Channel
{
    public string ChannelName { get; set; }

    public FileSets fileSets { get; set; }
}

public class FileSets : List<FileSet>
{
   
}

public class FileSet
{
    public string FileSetName { get; set; }
}
Workaround:
Use the the generic class instead of the inherited one:
public class DeskSites
{
    public string DeskSiteName { get; set; }

    public List<Channel> channels { get; set; }
}

To reproduce:

1. Add a RadTreeView with several nodes
2. Subscribe to the EditorRequired event and specify the editor to TreeViewTextBoxEditor where its Multiline property is set to true.
3. Select a node and press F2. The editor is activated. However, when you enter some text and press Ctrl+Enter, the editor is closed. The expected behavior is that a new line is inserted.

Workaround:

private void radTreeView1_EditorRequired(object sender, TreeNodeEditorRequiredEventArgs e)
{
    CustomTreeViewTextBoxEditor editor = new CustomTreeViewTextBoxEditor();
    editor.Multiline = true;
    e.Editor = editor;
}

public class CustomTreeViewTextBoxEditor : TreeViewTextBoxEditor
{
    protected override void OnKeyDown(KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Enter &&
            e.Modifiers == Keys.Control &&
            this.Multiline)
        {
            return;
        }
        base.OnKeyDown(e);
    }
}

Please refer to the attached gif file.

Workaround: set the Enabled property to false at run time.

Workaround:

private void radTreeView1_NodeFormatting(object sender, Telerik.WinControls.UI.TreeNodeFormattingEventArgs e)
        {
            e.NodeElement.UseDefaultDisabledPaint = true;
        }

Workaround:

class CustomDragDropService : TreeViewDragDropService
{
    public CustomDragDropService(RadTreeViewElement owner) : base(owner)
    {
        
    }

    protected override void SetHintWindowPosition(Point mousePt)
    {
    }
}

class CustomTreeViewElement : RadTreeViewElement
{
    protected override Type ThemeEffectiveType
    {
        get
        {
            return typeof(RadTreeViewElement);
        }
    }

    protected override TreeViewDragDropService CreateDragDropService()
    {
        return new CustomDragDropService(this);
    }
}

class CustomTreeView : RadTreeView
{
    protected override RadTreeViewElement CreateTreeViewElement()
    {
        return new CustomTreeViewElement();
    }

    public override string ThemeClassName
    {
        get
        {
            return typeof(RadTreeView).FullName;
        }
    }
}

To reproduce: 
1. Run Demo application >> TreeView >> Drag & Drop.
2. Change the theme to Windows7 and start dragging a node.

The drop hint is missing.

Workaround: apply the theme in the Form.Load event after getting the TreeViewElement.ItemDropHint property coming from the ControlDefault theme.

RadImageShape hint;

private void Form1_Load(object sender, EventArgs e)
{
    hint = this.radTreeView1.TreeViewElement.ItemDropHint;
    this.radTreeView1.ThemeName = "Windows7";
    this.radTreeView1.TreeViewElement.ItemDropHint = hint;
}

Similar functionality like in KendoUI or WPF

To reproduce: add a RadTreeView and a RadButton to the form. Use the following code snippet:

public Form1()
{
    InitializeComponent();

    RadTreeNode node1 = new RadTreeNode();
    node1.Text = "SameText";

    RadTreeNode node2 = new RadTreeNode();
    node2.Text = "SameText";

    this.radTreeView1.Nodes.Add(node1);
    this.radTreeView1.Nodes.Add(node2);

    this.radTreeView1.SortOrder = SortOrder.Ascending;
}

private void radButton1_Click(object sender, EventArgs e)
{
    for (int i = this.radTreeView1.Nodes.Count - 1; i > -1; i--)
    {
        this.radTreeView1.Nodes.RemoveAt(i);
    }
}

Workaround: set the SortOrder property to None before removing the nodes and restore it afterwards

private void radButton1_Click(object sender, EventArgs e)
{
    this.radTreeView1.SortOrder = SortOrder.None;
    for (int i = this.radTreeView1.Nodes.Count - 1; i > -1; i--)
    {
        this.radTreeView1.Nodes.RemoveAt(i);
    }
    this.radTreeView1.SortOrder = SortOrder.None;
}

Select Demo application >> "Tree View" -> "Drag & Drop". Focus on the left treeview.
1. Click on the node "Drafts";
2. Press Shift button and click on the "Outbox" node;
3. Release shift button;
4. Press left mouse button on the "Outbox" node and start dragging;
5. Drop selected nodes after node "Large Mail".

You can see that order of nodes was changed.
Before: "Drafts", "Inbox" and "Outbox"
After: "Outbox", "Drafts" and "Inbox"

Possible workaround: http://www.telerik.com/forums/nodes-order-after-drag-drop#5bbz6cBDEUeHLyLU5zkfDQ