I'm experimenting with new bindings for basic movement in Emacs. Borrowing from this page and ErgoEmacs, this remapping works as expected:
(global-set-key (kbd "M-i") 'previous-line)
(global-set-key (kbd "M-k") 'next-line)
(global-set-key (kbd "M-j") 'backward-char)
(global-set-key (kbd "M-l") 'forward-char)
But defining a Shift-Alt combination gives an unwanted side-effect.
(global-set-key (kbd "M-I") 'cua-scroll-down)
(global-set-key (kbd "M-K") 'cua-scroll-up)
(global-set-key (kbd "M-J") 'backward-word)
(global-set-key (kbd "M-L") 'forward-word)
Running describe-key (C-h k) shows that the bindings were successful. And these bindings move point as they should, but for some reason it sets the mark at my original position, and gives me a highlighted region as I move the point.
How do I correct this?
EDIT: This has something to do with cua-mode. When I disable cua-mode, the problem disappears. Unfortunately, disabling cua-mode is not a desirable solution.
EDIT: This is a bug in Emacs. It's tracked as bug#11221, title 'cua-mode activates the mark for shifted bindings'. From the discussion on the mailing list, it sounds like there will be a fix to cua-base.el.
It's indeed likely triggered by shift-select-mode, but it looks like a bug: shift-select-mode should pay attention to the fact that the command is bound to a shifted key. Try to reproduce the problem without using CUA and then please report it with M-x report-emacs-bug.