radDropDownList shows list twice

[Terry]

This issue can be seen in the Telerik Demo Application - UI for WinForms.  In the list at the left, select "DropDown & List".  From the DropDownList group of demos, select "Auto complete" (the one with the list of countries and their flags).  When the list is first displayed the dropdown list is opened and focus is in the keyin field.  Key in the letter 'C'.  You will see the list of countries that begin with 'C' over the original list of all countries.  See the attached image.

Is this a defect?  Is there a way to work around the issue?

[Ralitsa]

Hello Terry,

Thank you for contacting us. 

The observed case is an expected behavior because the ShowDropDown method is called right after the Focus method. If you want to prevent this behavior, you can use the code snippet below and hide the RadDropDownList`s popup: 

//subscribe to the PopupOpening event of the auto complete
this.radDropDownList1.DropDownListElement.AutoCompleteSuggest.DropDownList.PopupOpening += DropDownList_PopupOpening;

//close the RadDropDownList`s popup
void DropDownList_PopupOpening(object sender, CancelEventArgs e)
{
    this.radDropDownList1.CloseDropDown();
}

As an attachment, you can find a sample demo demonstrating the suggested solution. 

Hope this will help you. Let me know if you have any other questions.

Regards,
Ralitsa
Telerik by Progress

[Terry]

I marked Ralitsa's post as the answer, because it works with only a minor side-effect, but we are baffled as to why the RadDropDownList has separate popups for the down arrow and for the AutoCompleteSuggest.  This allows two different popups to be visible at the same time which is confusing and unattractive.

[Ralitsa]

Hi Terry,

Thank you for sharing your experience. 

The observed behavior with overlapped popup is by design. For reference, standard Microsoft`s ComboBox control has the same behavior. However, we have already logged the same request in our Feedback Portal. You can track its progress, subscribe for status changes and add your vote/comment to it on the following page: FIX. RadDropDownList - the control popup is not closed automatically when the auto-complete popup is shown, hence both popups overlap. 

Please do not hesitate to contact us if you have any additional questions.

Regards,
Ralitsa
Telerik by Progress