HI,

I have been looking at using your xamComboEditor with filtering and have identified what I believe to be a bug. In your combo box you appear to use the Popup with relative placement. By default the Popup appears under the control unless there is not enough screen space, in which case it appears above the control, as expected. A problem occurs due to the filtering. When clearing text in the control which would result in more items appearing in the Popup, the placement always changes to below the control, rather than the appropriate placement for the screen position. The result of this is that if Popup is above the control (because it will not fit below), when the Popup expands it attempts to place it below, but instead will go as low as possible, resulting in the control being covered by the Popup. This is clearly an unacceptable user experience, so needs to be addressed.

This problem can be observed on your own xamFeatureBrowser shipped with NetAdvantage for WPF. Go to the xamComboEditor -> Key Features -> Read-Only And AutoComplete. On the “Google Suggest Style – filtered items list” combo, and type ‘a’, then delete the ‘a’. You will see the Popup expand to show entries beginning with ‘a’, and the Popup expand over the control when the ‘a’ is deleted. If you don’t observe this then move the application to the bottom of the screen before you type in the combo.

Could you please suggest any work-around, until this is fixed, to provide acceptable usability. I attempted to create and use a custom Popup in the template for your control, but the CustomPopupPlacementCallback does not appear to get called when the Popup expands and is moved to below the control (note I was forcing Custom placement before the open of the Popup).

Thanks for your time.