The scrollbar appears normally when changing the following (provided content overflows new text box size):
* Decreasing the width.
* Increasing the width.
* Increasing the height.
However, the scrollbar does not appear when:
* Decreasing the height.
1.) Add RichTextBox2 to a form.
2.) Wire-up events on form resize.
3.) Have these events also resize the RichTextBox2 proportionally.
4.) Add content to the RichTextBox2 that forces the vertical scrollbar to appear.
5.) Resize form in all four directions, and note that the scrollbar is not rendered when decreasing the form's (and RichTextBox2's) height. After this, the scrollbar is then rendered when the form is resized in any other direction.