This exception is a result of changes in the Current property of the IEnumerator interface. With the lastest version, if the current item is undefined it will throw an exception if we try to access it with the Current property, while in the older version, it will return null.

RadSplitButton does not get a focus rectangle when focus by the Tab key. One should first click the action part and then the focus rectangle will appear..

The current workaround is:
public class MyRadSplitButton : RadSplitButton 
{ 
    protected override void OnEnter(EventArgs e) 
    { 
        base.OnEnter(e); 
  
        this.DropDownButtonElement.ActionButton.Focus(); 
    } 
}

This item is migrated to the Telerik Document Processing portal: 
http://feedback.telerik.com/Project/184/Feedback/Details/190124 
Please use the new item for commenting, voting and subscribing instead of this one.

Use attached to reproduce.

Workaround:

- Use RadForm it explicitly handles the controls scaling. 
- Make sure that the following of the user controls are set like this:

this.AutoScaleDimensions = new System.Drawing.SizeF(96F, 96F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Dpi;