I updated to 3.6 today and was working on a post.
It was working fine until it suddenly stopped responding to my commands.
I have a picture inserted and centred on the page.
Below is centred text, explaining the pic.
Below that, I want a double-space, then the centred sub-heading of the next topic.
It refuses to respond to my request for double-spacing.
It will insert spaces and any other modifications I request except this.
I have already emptied my cache and have disabled all plugins.