If you try to style the Right column menu of RadApplicationMenu, your changes will not be persisted and applied to the control.

Workaround: 
FillPrimitive fill = (FillPrimitive)this.radRibbonBar1.RibbonBarElement.ApplicationButtonElement.DropDownMenu.RootElement.Children[0].Children[0].Children[2].Children[0].Children[2].Children[1].Children[0];
fill.BackColor = Color.Orange;
fill.BackColor2 = Color.Red;

To reproduce: 
1. Add a new form 
2. Drag and drop RadApplicationMenu on the form
3. Add RadMenuSeparatorItem at design time 
4. Save the form
5. Press Ctrl + Z to undo changes 
6. Press Ctrl + Y to redo changes 
7. An exception is thrown with message: Object of type 'System.Boolean' cannot be converted to type 'Telerik.WinControls.ElementVisibility'.

Add text to separator items

Workaround:

 foreach (RadMenuItem item in radMenu1.Items)
            {
                item.Layout.Text.Font = new Font("Tahoma", 12, FontStyle.Bold);
            }

When right clicking on a control near the bottom of the screen, the context menu (implemented as a RadContextMenu) opens downwards from the point where the mouse was clicked. This results in the majority of the menu going off the bottom of the screen.

On subsequent right clicks in the same area, the context menu opens upwards from the click position, which is correct functionality as the menu is not obscured.

The menu is shown by calling:
contextMenu.Show(viewerControl, e.Location);

The bug occurs the first time that the context menu is shown on a control.

To reproduce: 
1. Drag and drop RadMenu on form. 
2. Add few items
3. Set design time the ForeColor of of RadMenuItem to red.  The ForeColor is changed.
4. Run the form and you will see that the ForeColor of RadMenuItem is black again. 

Workaround:  
1. Set the ForeColor run time using following code  snippet: 
this.radMenuItem1.ForeColor = Color.Red;
 
2. Set the ForeColor of TextPrimitive through Element hierarchy editor. You can see the DesignTimeSetForeColorOfRadMenuItem.png image how to set it.  

You can use following workarounds:

1)The menu items are components and you can edit any menu item directly in your code. For example:
this.radMenuItem10.Click+=menuItemClickMethod;

Also you can selected and edit them in these ways:

2) Selected a particular menu item via Visual Studio's Document Outline window (ctrl+W, U). Then you will be able to selected the desired item from the hierarchy. After that item will be selected in the property grid and you can add/remove events and edit its properties.

3) You can select a specific menu item directly via Visual Studio's Property Grid's Component combobox (on the top of the property grid)

To reproduce: 
1. Add RadForm and set the following properties at design time: 
this.AutoSize = true;
this.WindowState = FormWindowState.Maximized;
this.Size = new Size(750, 500); 
2. Add RadMenu and add more than 10 menu items
3. Run the application and you will see that menu items are overlapped (see the attached image)

Workaround: 
Restore the WindowState of form to Normal at design time and set the WindowState to Maximized run time in the Load event of form. Here is the snippet: 
private void RadForm1_Load(object sender, EventArgs e)
{
    this.WindowState = FormWindowState.Maximized;
}

The default value of the RadMenuButtonItem.TextImageRelation property was ImageBeforeText until Q3 2014 after which it has changed to Overlay.

To reproduce: Try to set a tooltip for RadButtonElement in RadApplicationMenu during design time

Currently RadMenu and its drop down menus does not behave correctly when used in right to left mode.

The ToolTipTextNeeded event is not fired for the menu items that appear in a menu popup

Add two menu items to a context menu and set their texts to "&Command 1" and "&Command 2". Add some actions to to be executed when each is clicked. Set the visibility of the first one to hidden or collapsed and run the project. Open the context menu and press the "C" key. You will see that the action of the first menu item will be executed although only the second is visible in the context menu.

To reprodue:
-Add a RadMenu with several items and sub items.
-Add shortcuts for some of the sub items (e.g. CTRL + SHIFT + A).
-Run the application and press CTRL + SHIFT + A. As a result the Click event for the specific items is fired. This is correct behavior.
-If you add a RadButton, which Click event shows a RadMessageBox and display the message box before pressing CTRL + SHIFT + A, the Click event for the certain item is fired again, although the main form is currently not active.

Workaround:
public class CustomRadMenuItem : RadMenuItem
{
    public CustomRadMenuItem(string text) : base(text)
    {
    }

    protected override Type ThemeEffectiveType     
    { 
        get    
        { 
            return typeof(RadMenuItem);     
        }
    }

    protected override bool CanHandleShortcut(ShortcutEventArgs e)
    {
        Control owner = this.OwnerControl;
        if (owner == null)
        {
            return false;
        }

        Form form = owner.FindForm();

        if (form == null)
        {
            RadDropDownMenu toolTipOwner = owner as RadDropDownMenu;
            if (toolTipOwner != null && toolTipOwner.Owner != null)
            {
                form = ((RadMenuElement)this.Owner).ElementTree.Control.FindForm();
                if (form != null)
                {
                    Form activeForm = e.FocusedControl == null ? Form.ActiveForm : e.FocusedControl.FindForm();
                    return form == activeForm || form.ContainsFocus;
                }
            }
        }

        return base.CanHandleShortcut(e);
    }
}

If you have a RadMenu that has more items than what can fit on the screen, once the menu opens for the first time on a second monitor, it doesn't show you the whole menu and. If you open the menu for a second time, it is OK

ButtonElements in RadMenuButtonItems are not shown correctly, their are cut from the right side.

Adding that are not RadMenuItemBase derivates should not be allowed.

If there is a need for custom elements in the dropdownmenu, these elements should be hosted by a RadMenuItemBase derivative (for example RadMenuItem)

There should be a convenient API which can be used to hide/show/rotate the arrows of RadMenuItems.