You can do something like this in the UltraToolbarsManager.BeforeToolDropdown event:

 if (e.Tool.Key == "GridContextMenu" && e.SourceControl == this.grid)
{
 UIElement element = this.grid.DisplayLayout.UIElement.ElementFromPoint(Control.MousePosition);
 UltraGridCell cell = (UltraGridCell)element.GetContext(typeof(UltraGridCell));

 PopupMenuTool contextMenu = (PopupMenuTool)e.Tool;

 if (cell != null)
 {
  contextMenu.Tools["Tool1"].InstanceProps.Visible = DefaultableBoolean.False;
  contextMenu.Tools["Tool2"].InstanceProps.Visible = DefaultableBoolean.True;
  // ...
 }
 else
 {
  // ...
 }
}

Can you please give me the sample code of Mouse_Up event? Thanks in advance

You can also respond to the BeforeToolDropdown event of the toolbars manager. If the key of the tool dropping down is your context menu tool's key and the SourceControl property of the event args is your grid control, you can then update the context menu based on the current mouse position (Control.MousePosition or Cursor.Position).

Hi Dave,

    There are a couple of ways to do this.

    1) Change the ContextMenuUltra dynamically as the mouse moves over the control. This is not very efficient because you will have to use UIElements to determine what part of the grid the mouse is over and most of the time it will be unneccessary, since the user only right-clicks on the right once in a while. 

    2) Use the MouseUp event. Note that I say MouseUp, not MouseDown. If you test other Windows applications you will see that they never show a context menu on a MouseDown, it's always a MouseUp. Using MouseDown will cause problems with mouse message because the control will get the MouseDown, but then the MouseUp message gets lost.