I'm using emacs and auctex to write LaTeX documents. For some reason, M-e doesn't move to the end of the sentence in tex-mode as it did when I went through the tutorial. It moves to the end of the paragraph. (That is, it moves to just before the next double line break)
What is wrong? Do I need to turn on/off some mode to skip to the next full stop? How do I check which modes are active?
The first thing to check is what M-e is bound to. In tex-mode, for me, it is bound to forward-sentence. You find this out by C-h k M-e.
It sounds as though it's bound to forward-paragraph, in which case I'd check your .emacs file to see if you've got any overrides in tex-mode hooks, or other things. You can also try running without your .emacs: emacs -q, and seeing what M-e is bound to (to determine if it truly is your .emacs). You can also start without the site lisp file emacs -q --no-site-file - in case your administrators have added anything.
I noticed that the same happens in my Emacs. The problem is that the variable sentence-end-double-space is set to t. This means that Emacs expects a sentence to end with a double space. By setting to nil things work properly, i.e., Emacs recognizes a period followed by a single space as the end of sentences.