The default behavior when the focus is inside an input control and it's Text is changed is that it's caret is placed in the beginning of the next text. This could be observed in the WPF TextBox control. In certain scenarios modifying the SearchText while the focus is inside the control is a desired behavior. In those scenarios the caret position is expected to be set to the end of the new text which is set to the SearchText property.
Is nice to see that this bug have been cought by Telerik and sad that a solution have not being found/Implemented since 2014.
From out side we found that only when you set the SearchText from code behind is this being a probem for us. We have not tested the AutoCompletebox without focus though. The Populate method and the userInput seems to work perfectly.
Our work around was to access the Textbox inside the control and set the caret of it to the end everytime we use code behind.
```
private static void SetCaretToTheEndByFindingTheTextboxControl(RadAutoCompleteBox completeBox)
{
//https://feedback.telerik.com/wpf/1352291-autocompletebox-changing-the-searchtext-when-the-focus-is-inside-the-control-should-set-the-caret-position-to-the-end-of-the-new-text
//When completeBox.SearchText is set from code behind the caret is not changed
if (completeBox == null)
return;
var textbox = completeBox.FindChildByType<TextBox>();
if(textbox != null)
{
textbox.CaretIndex = textbox.Text.Length;
return;
}
var waterMarkTextbox = completeBox.FindChildByType<RadWatermarkTextBox>();
if (waterMarkTextbox != null)
{
waterMarkTextbox.CaretIndex = waterMarkTextbox.Text.Length;
return;
}
}
```
Our scenario is a textbox that suggest some input but where the text displayed on the Textbox is different from the Itemlist displayed item. for that porpouse we implemented an attached property that is modifying the SearchText when the selection change (another improvement for the AutocompleteTextBox that could be easily implemented from your side) The AutocompleteBox in selection mode single was working better than suggestionBox Control.
