Arrow Key Actions for Selected Text
If a region of text is selected (that is, the selStart field of the edit record does
not equal the selEnd field) and a user presses either the Up Arrow or Down
Arrow key, the caret moves from the beginning of the selected region (or the
selStart position). If the user presses the Right Arrow key, the caret appears
one character to the right from the end of the highlighted region, and if the
user presses the Left Arrow key, the caret appears one character to the left
from the beginning of the selected text.