How to reproduce: associate the control with an object having a Font property. It can be the form itself, then try and change the font-size, e.g: -1.

The standard property grid displays a message box with the error.

Workaround handle the RadPropertyGrid.EditorInitialized event:
private void RadPropertyGrid_EditorInitialized(object sender, PropertyGridItemEditorInitializedEventArgs e)
{
    PropertyGridSpinEditor editor = e.Editor as PropertyGridSpinEditor;
    if (editor != null && e.Item.Parent != null && e.Item.Parent.Name == "Font" && e.Item.Name == "Size")
    {
        editor.MinValue = 1;
    }
}

This should work similar to RadGridView. Once should be able to manually set the height of on individual rows as well.

To reproduce:

            this.radPropertyGrid1.SelectedObject = this;             
            this.radPropertyGrid1.PropertyGridElement.SplitElement.HelpElement.MinSize = new Size(0, 60);

Please refer to the attached gif file.

Workaround:

            this.radPropertyGrid1.SelectedObject = this;             
            this.radPropertyGrid1.PropertyGridElement.SplitElement.HelpElement.MinSize = new Size(0, 60);
            this.radPropertyGrid1.PropertyGridElement.SplitElement.HelpElement.HelpTitleElement.MinSize = new Size(0,20);

            this.radPropertyGrid1.PropertyGridElement.SplitElement.HelpElement.HelpTitleElement.PropertyChanged += HelpTitleElement_PropertyChanged;

        private void HelpTitleElement_PropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName == "Bounds")
            {
                if (this.radPropertyGrid1.PropertyGridElement.SplitElement.HelpElement.HelpContentElement.Location.Y != 20)
                {
                    this.radPropertyGrid1.PropertyGridElement.SplitElement.HelpElement.HelpContentElement.Location = new Point(0, 20);
                }
            }
        }

Note: the description element may be floating but it doesn't overlap the title. 

To reproduce:

    Sub New()

        InitializeComponent()

        Dim intItem As New PropertyStoreItem(GetType(Integer), "Integer", 1)
        Dim floatItem As New PropertyStoreItem(GetType(Single), "Float", 1.0F, "Property storing a floating point value.")
        Dim stringItem As New PropertyStoreItem(GetType(String), "String", "telerik", "Property storing a string value", "Telerik")
        Dim fontItem As New PropertyStoreItem(GetType(Font), "Font", New Font("Arial", 12, FontStyle.Italic), "Property containing Font value")

        fontItem.Attributes.Add(New ReadOnlyAttribute(True))
        floatItem.Attributes.Add(New ReadOnlyAttribute(True))
        Dim store As New RadPropertyStore
        store.Add(intItem)
        store.Add(floatItem)
        store.Add(stringItem)
        store.Add(fontItem)
        Me.RadPropertyGrid1.SelectedObject = store
    End Sub

Try to edit either the "Float" or the "Font" property. The editor will be activated although it doesn't have to.

Workaround: cancel the Editing event

    Private Sub RadPropertyGrid1_Editing(sender As Object, e As PropertyGridItemEditingEventArgs)
        If e.Item.Name = "Font" Then
            e.Cancel = True
        End If 
    End Sub

Use attached to reproduce. 

Workaround
radPropertyGrid1.ItemSpacing = 1;

Use attached to reproduce.
- Type 'n' in the search bar 
- "Name" is not found

To reproduce: use the following code snippet and follow the steps from the gif file:

            PropertyStoreItem item1 = new PropertyStoreItem(typeof(string), "Test1", "Test1");
            PropertyStoreItem item2 = new PropertyStoreItem(typeof(string), "Test2", "Test2");
          
            RadPropertyStore store = new RadPropertyStore();
            store.Add(item1);
            store.Add(item2); 
            this.radPropertyGrid1.SelectedObject = store;

            this.radPropertyGrid1.ToolbarVisible = true;

Workaround: close the editor programmatically when the search box gets focus.

this.radPropertyGrid1.PropertyGridElement.ToolbarElement.SearchTextBoxElement.TextBoxItem.GotFocus += TextBoxItem_GotFocus;

        private void TextBoxItem_GotFocus(object sender, EventArgs e)
        {
            this.radPropertyGrid1.EndEdit();
        }

How to reproduce: run the attached project on a system with an increased scaling - 200%

How to reproduce: check the attached screenshot

Workaround: use the attached custom theme

Please refer to the attached video illustrating the incorrect behavior of the context menu.

Workaround:

        public RadForm1()
        {
            InitializeComponent();

            this.radPropertyGrid1.SelectedObject = this;
            this.radPropertyGrid1.ToolbarVisible = true;

            this.radPropertyGrid1.RadContextMenu = new CustomPropertyGridDefaultContextMenu(this.radPropertyGrid1.PropertyGridElement.PropertyTableElement);
        }

        public class CustomPropertyGridDefaultContextMenu : Telerik.WinControls.UI.PropertyGridDefaultContextMenu
        {
            PropertyGridTableElement tableElement;

            public CustomPropertyGridDefaultContextMenu(PropertyGridTableElement propertyGridElement) : base(propertyGridElement)
            {
                tableElement = propertyGridElement;
            }

            protected override void OnDropDownOpening(CancelEventArgs args)
            {
                base.OnDropDownOpening(args);
                PropertyGridItemBase item = this.tableElement.SelectedGridItem;
                if (item != null)
                {
                    if (!(item is PropertyGridGroupItem))
                    {
                        this.EditMenuItem.Visibility = ElementVisibility.Visible;
                        this.ResetMenuItem.Visibility = ElementVisibility.Visible;
                    }
                }
            }
        }

To reproduce:

        public RadForm1()
        {
            InitializeComponent();
             
            this.radPropertyGrid1.SelectedObject = new Item("zero", "uniqueId","alpha");

            this.radPropertyGrid1.EnableSorting = true;
            SortDescriptor sort = new SortDescriptor("Value", ListSortDirection.Ascending);
            this.radPropertyGrid1.SortDescriptors.Add(sort);
        }

        public class Item
        {
            public string Text { get; set; }
            
            public string Identifier { get; set; }

            public string Value { get; set; }

            public Item(string text, string identifier, string value)
            {
                this.Text = text;
                this.Identifier = identifier;
                this.Value = value;
            }
        }

Workaround#1: Set SortOrder to None

this.radPropertyGrid1.SortOrder = SortOrder.None;

Workaround#2: use a custom comparer:
            this.radPropertyGrid1.SortDescriptors.Add(sort);

            this.radPropertyGrid1.PropertyGridElement.PropertyTableElement.ListSource.CollectionView.Comparer = new MyComparer();

        public class MyComparer : IComparer<Telerik.WinControls.UI.PropertyGridItem>
        {
            int IComparer<Telerik.WinControls.UI.PropertyGridItem>.Compare(Telerik.WinControls.UI.PropertyGridItem x, Telerik.WinControls.UI.PropertyGridItem y)
            {
                if (x.Value != null && y.Value != null)
                {
                    return x.Value.ToString().CompareTo(y.Value.ToString());
                }
                return 0;
            }
        }

To reproduce:
- Add RadPropertyGrid to a form and set the theme to MaterialTeal. The issue is observed in the ThemeViewer as well.

Workaround:
radPropertyGrid1.PropertyGridElement.ToolbarElement.AlphabeticalToggleButton.TextWrap = true;
radPropertyGrid1.PropertyGridElement.ToolbarElement.CategorizedToggleButton.TextWrap = true;
//or

 radPropertyGrid1.PropertyGridElement.ToolbarElementHeight = 68;

Office2010silver theme showing different result with  2017.2.613 version my font size became very small.

Please run the attached sample project and refer to the attached screenshots. RadPropertyGrid doesn't respect the Description attribute.

 this.radPropertyGrid1.SelectedObject = new Item(123,"Item", ExposureMode.FullAuto);

public class Item
{
    public int Id { get; set; }

    public string Name { get; set; }

    public ExposureMode Mode { get; set; }

    public Item(int id, string name, ExposureMode mode)
    {
        this.Id = id;
        this.Name = name;
        this.Mode = mode;
    }
}

public enum ExposureMode
{
    [Description("Full Auto")]
    FullAuto,
    [Description("Auto Filter, Fixed Exposure")]
    AutoFilFixedExp,
    [Description("Fixed Filter, Auto Exposure")]
    FixedFilAutoExp,
    [Description("Fixed Filter, Fixed Exposure")]
    FullFixed
}

Workaround use the attached custom theme: http://docs.telerik.com/devtools/winforms/themes/using-custom-themes

RadSpinEditor now supports null values. This functionality is relevant for the PropertyGridSpinEditor as well  http://docs.telerik.com/devtools/winforms/editors/spineditor/null-value-support

Use attached project to reproduce!
This works fine in  2016.2.608.

Workaround:
Use singe RadPropertyStore object instead of an array.

To reproduce: please refer to the attached sample project. Try to select a new value from the drop-down editor and press Yes from the message box.

Workaround: use the RadPropertyGrid.PropertyValueChanging event to confirm the property changing: 

private void radPropertyGrid1_PropertyValueChanging(object sender, Telerik.WinControls.UI.PropertyGridItemValueChangingEventArgs e)
{
    e.Cancel = (MessageBox.Show("Are you sure you want to change this?", "Question", MessageBoxButtons.YesNo) != DialogResult.Yes);
}

Please refer to the attached sample project.

Please refer to the attached gif file demonstrating how to reproduce the error with the Demo application.

Workaround: change the DropDownStyle property to DropDownList:

private void radPropertyGrid1_EditorInitialized(object sender, PropertyGridItemEditorInitializedEventArgs e)
{
    PropertyGridDropDownListEditor editor = e.Editor as PropertyGridDropDownListEditor;
    if (editor!=null)
    {
        BaseDropDownListEditorElement editorElement = editor.EditorElement as BaseDropDownListEditorElement;
        editorElement.DropDownStyle = Telerik.WinControls.RadDropDownStyle.DropDownList;
    }
}