After upgrading to Emacs 24.4.1, when I call org-agenda with no splits it will show on the bottom half of the frame. Previously, it would show on the right half. How do I configure this behaviour?
I believe this behavior is not specific to org-agenda, but rather depends on the size of the window and the variables
split-height-threshold. If your window is wide enough the agenda will open on the right.
You may want to try a lower
split-width-threshold if you prefer to split things vertically (new window on the right). If you really only want to do this for org-agenda, some advice might work:
(defadvice org-agenda (around split-vertically activate) (let ((split-width-threshold 80)) ; or whatever width makes sense for you ad-do-it))
Another option is to define a command to toggle from a horizontal split to a vertical split, as described here: http://whattheemacsd.com/buffer-defuns.el-03.html
I combined the toggle-window-split function from http://whattheemacsd.com/buffer-defuns.el-03.html with advicing and it works pretty well:
See that the toggle-window-split function is available/loaded and advice like so:
(advice-add 'org-agenda :after #'toggle-window-split)