Getting Value Selected By Mouse Click.

Solution Found.   

https://www.telerik.com/forums/which-event-to-subcribe-when-user-clicks-on-drop-down-list-from-textbox-auto-complete-suggestions

Had to subscribe to:

Register this in the Load or Initialize event

this.racContentTypeOfDoc.ListElement.ElementTree.Control.Click += this.OnListElementClick;

Then code this Event.  In my case I was taking the item and putting it in a text box then "Clearing Out" the selected item.

private void OnListElementClick(object sender, EventArgs e)
        {
            ComponentThemableElementTree elementTree = this.racContentTypeOfDoc.ListElement.ElementTree;
            Point mousePosition = elementTree.Control.PointToClient(Control.MousePosition);
            RadElement element = elementTree.GetElementAtPoint(mousePosition);

            while (element != null)
            {
                RadListVisualItem item = element as RadListVisualItem;

                if (item != null)
                {
                    if (txtSearch.Text.Trim().Length > 0)
                        if (rbOr.Checked)
                            txtSearch.Text += " OR (";
                        else
                            txtSearch.Text += " AND (";
                    else
                        txtSearch.Text = "(";
                        txtSearch.Text += item.Text;
                    txtSearch.Text += ")";
                    break;
                }

                element = element.Parent;
            }
            racContentTypeOfDoc.Clear();
        }

Hello, Roger,

According to the information in your second post, it seems that you managed to found a working solution for your case. I am really glad that handling the ListElement.ElementTree.Control.Click event helps you do the job. 

In case you have any other questions do not hesitate to contact us.

Regards,
Nadya
Progress Telerik