Growing and Shrinking of HtmlTextBox
By default, the HtmlTextBox report item has its size set.
To allow the HtmlTextBox to expand vertically based on its content, set its CanGrow property to its default True value.
To allow the HtmlTextBox to shrink based on its content, set its CanShrink property to True. By default, CanShrink is set to False. Note that the HtmlTextBox will always grow to accommodate the first line of text even when CanGrow is False.