How to left align the text of the ComboBoxItem when it is too long
If the text in a RadComboBoxItem is longer than the width of the ComboBox itself and the ComboBox is in editable mode, when you focus RadComboBox it selects all of its text and the cursor is at the end of the word for easy edition.
To make it left aligned and remove the selection you can set the SelectAllTextEvent property of the ComboBox to None.
The described approach is only available if the selection is done via mouse click or keyboard navigation. If an item is selected by the AutoComplete functionality of the control the text will not be aligned to the left.
