+ After switching windows or buffers, and in some other cases, if the
+window start is in the middle of a line, Emacs adjusts the window
+start to the start of a line. This prevents certain operations from
+leaving the window start at a meaningless point within a line. This
+feature may interfere with testing some Lisp code by executing it
+using the commands of Lisp mode, because they trigger this
+readjustment. To test such code, put it into a command and bind the
+command to a key.
+