Recently I've changed titles of some of my articles in a WP 2.3 blog. Example: I've changed "Constipation - Diagnosis and Treatment" into "Chronic Constipation - Diagnosis and Treatment" http://www.healthhype.com/constipation-diagnosis-and-treatment.html Then I've noticed that <title> tag has not changed! (I've changed the title from a post editor). It's been months when I've changed it. If I try again, no effect again. The same happened in some other (but not all!) titles. What's wrong?
Maybe you are using a different field to specify the title, i'm not too sure, as an alternative you can always install the All in one SEO pack which gives you full control of titles, keywords and descriptions for every post.
Yes, it was All in One SEO Pack issue. I've just forgot to change title there. Now it works. The point was, that I've also changed some text in post body - and this worked...but title has not changed . Cheers.