Excuse me for my bad English :-)
Shift+arrows is traditional hotkeys for select text in text editor.
Midnight commander has "mcedit" text editor. It supports text selection with
Shift+arrows. This feature works with xterm (xterm -v: X.Org 18.104.22.1683(243))
but does not work with RoxTerm 1.13.0.
Righter: shift+left/right works, shift+up/down does not.
Midnight commander's version is 4.7.0-pre4
(http://www.midnight-commander.org/downloads), OS is Slackware 13.0.
Please note about clipbuffer copy/paste hotkeys also:
ctrl+insert = copy to buffer (does not work by default)
shift+insert = insert from buffer (works!)