RadMultiColumnComboBox should support suggest and suggest-append auto-complete modes when AutoFiltering is enabled.

FIX. RadMultiColumnComboBox. Setting the FormatString to a numeric column to some currency format and changing the column position results in displaying an invalid currency symbol.

This feature request refers to implementation of an AutoComplete mode for RadMultiColumnComboBox.

To reproduce:
void Form1_Load(object sender, EventArgs e)
{
    this.radMultiColumnComboBox2.AutoSizeDropDownToBestFit = true;

    RadMultiColumnComboBoxElement multiColumnComboElement2 = this.radMultiColumnComboBox2.MultiColumnComboBoxElement;

    multiColumnComboElement2.EditorControl.MasterTemplate.AutoGenerateColumns = true;

    DataTable dt = GetDataTable();
    this.radMultiColumnComboBox2.DataSource = dt;

    FilterDescriptor descriptor3 = new FilterDescriptor("Station", FilterOperator.Contains, null);
    this.radMultiColumnComboBox2.EditorControl.FilterDescriptors.Add(descriptor3);

    FilterDescriptor descriptor4 = new FilterDescriptor("StationName", FilterOperator.Contains, null);
    this.radMultiColumnComboBox2.EditorControl.FilterDescriptors.Add(descriptor4);

    this.radMultiColumnComboBox2.EditorControl.FilterDescriptors.LogicalOperator = FilterLogicalOperator.Or;

    radMultiColumnComboBox2.AutoFilter = true;
}

private DataTable GetDataTable()
{
    DataTable dt = new DataTable();

    dt.Columns.Add("Station"); //, typeof(Int32));
    dt.Columns.Add("StationName");

    System.Data.DataRow row1 = dt.NewRow();
    System.Data.DataRow row2 = dt.NewRow();
    System.Data.DataRow row3 = dt.NewRow();
    System.Data.DataRow row4 = dt.NewRow();
    System.Data.DataRow row5 = dt.NewRow();
    System.Data.DataRow row6 = dt.NewRow();
    System.Data.DataRow row7 = dt.NewRow();
    System.Data.DataRow row8 = dt.NewRow();
    System.Data.DataRow row9 = dt.NewRow();
    System.Data.DataRow row10 = dt.NewRow();

    row1["Station"] = "285";
    row1["StationName"] = "Bob";

    row2["Station"] = "274";
    row2["StationName"] = "Mary";

    row3["Station"] = "222";
    row3["StationName"] = "Joan";

    row4["Station"] = "289";
    row4["StationName"] = "William";

    row5["Station"] = "385";
    row5["StationName"] = "Bob";

    row6["Station"] = "374";
    row6["StationName"] = "Mary";

    row7["Station"] = "331";
    row7["StationName"] = "Jane";

    row8["Station"] = "389";
    row8["StationName"] = "William";

    row9["Station"] = "281";
    row9["StationName"] = "Bob";

    row10["Station"] = "273";
    row10["StationName"] = "Mary";

    dt.Rows.Add(row1);
    dt.Rows.Add(row2);
    dt.Rows.Add(row3);
    dt.Rows.Add(row4);
    dt.Rows.Add(row5);
    dt.Rows.Add(row6);
    dt.Rows.Add(row7);
    dt.Rows.Add(row8);
    dt.Rows.Add(row9);
    dt.Rows.Add(row10);

    return dt;
}

Start the application and type 2738 (273 is the last row), then press the up arrow twice, exception should occur.

Workaround:
public class MyRadMultiColumnComboBox : RadMultiColumnComboBox
{
    protected override RadMultiColumnComboBoxElement CreateMultiColumnComboBoxElement()
    {
        return new MyRadMultiColumnComboBoxElement();
    }
}

public class MyRadMultiColumnComboBoxElement : RadMultiColumnComboBoxElement
{
    protected override void ProcessKeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Up)
        {
            GridViewRowInfo row = this.GetCurrentRow(true);
            if (row != null)
            {
                int index = row.Index;
                if (index == -1)
                {
                    if (this.Rows.Count > 0)
                    {
                        this.EditorControl.CurrentRow = this.Rows[0];
                    }

                    return;
                }
            }
        }

        base.ProcessKeyDown(sender, e);
    }

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

Steps to reproduce:
1. Bind a RMCCB to some data source
2. Enable auto filtering
3. Start the app and enter a value in the text editor of RMCCB
4. Press Tab. You will see that the focus is moved away from the RMCCB but the selection is not changed. Also if you try to open the drop down you will see that it has wrong size. Hitting Escape or Enter instead of Tab produces the correct behavior.

FIX. RadMultiColumnComboBox - when a row with null value is selected, instead of an empty string, the editor displays "Telerik.WinControls.UI.GridView"

When auto filter is enabled and filtering is applied, you cannot select the correct item by mouse.

The RadMultiColumnComboBox throws exceptions if its data source is empty and the AutoSizeDropDownToBestFit property is set to true.

1. Create a new project with RadMultiColumnComboBox
2. Add rows in unbound mode
3. On a timer clear the Rows collection and insert new rows
4. Run the application and open and close the drop down several times

Using my two screenshots and values, note:
 1. Using Keyboard: I have 'A' selected and type a single 'W' to change my selection and hit enter. The next drop-down will still display at the width you see for the original A selection.  It will not be until the next drop-down that it resizes correctly.
 2. Using Mouse: I have 'A' selected and select the 'WWWW...." from the drop-down with my mouse.  The drop-down will appear correctly the next time.

Current row is selected in RadMultiColumnComboBox when the mouse's left button is released.

Set the AnimationEnabled property of RadCalendar and DropDownAnimationEnabled property in RadMultiColumnComboBox to false and there will be no effect.

When auto-filtering is applied to RadMultiColumnComboBox and mouse double click is performed over a row, the selected row is changed to another row.

When you select a row by pressing the left mouse button twice, you will select a wrong row if RadMultiColumnComboBox has filter applied.

radMultiColumnComboBox €“ set AutoFilter to be true and apply filter to radMultiColumnComboBox. Apply the filter in this way so no result is displayed in the drop down. Try to open the drop down and you will see that you cannot.

The RadMultiColumnComboBox control does not update its selection when the user types text in the text field.
The expected behavior is that when the user types text and there is a databound item that matches the input, it should be selected. Otherwise, the current selection in the list should be cleared.

TextChanged event of RadMultiColumnComboBox is not fired on many occasions.