Selects all text within the text box.
This method enables you to select all text within the control. Note that end-users can select the entire text box's content using the built-in context menu or the F2 key. You can use the SelectAll method if you need to provide additional methods for selecting the editor's content. You may also need to facilitate end-user input using this method. For instance, you can select the entire editor's content when an editor receives focus.