A text file, say in an rtb, when selected by mouse
or key, is selected by rows.
I want to be able to select by rectangle with the mouse.
The rectangle area should be blue as it expands.
After deleting, the rectangle and all text it covered
should be gone, but the displayed file should not
contract. The deleted text area would just be blank.
In this manner, you could delete a column of text,
say, a column of figures, from the center of the
document, without affecting the rest of the doc.
