I'm pretty sure the <p class="calibre7"> </p> is coming from the insert blank line option being enabled. I never use that option, but a review of the code corroborates that.
There have been a lot of bug fixes/improvements lately - Lit input had a bug in it where it was treating all content in <pre> tags as 'block', and that didn't work for the majority of Lit files using <pre> tags. So if Lit input detects a <pre> tag it now does text processing using 'Single', and a user can enable heuristics if they need unwrapping.
Text input also had improvements where it's preserving soft scene breaks - i.e. empty lines. It's possible that a document that is both 'single' and 'block' - i.e. single line paragraphs with a blank line in between each one - might cause text input to create a lot of blank paragraph markers. If so, the 'delete blank paragraphs' option in heuristics would detect and get rid of those.
The insert blank line option happens much further down the pipeline, looks like after remove paragraph spacing but before css rationalization - though I always thought remove paragraph spacing was part of css rationalization, maybe that happens during rationalization but before the user defined css is applied. Anyway in my experience if you use user defined css it will basically do the same thing as the checkbox, which your css settings and result corroborate.
It sounds to me like you found a workflow that was working around old bugs, and now that some of that has been fixed you're seeing your old workflow impacted. That's just a guess though - It would take a bit of investigation to confirm - old and new versions of Calibre, etc.
I think disabling insert blank line and increasing the margins in your extra css would probably be the best option for you, unless there really is a bug to be fixed, but I'm not sure I see one.
Last edited by ldolse; 02-10-2011 at 06:46 AM.