paragraph spacing editing in Calibre

[fionamarg]

I've downloaded Calibre so that I can make small adjustments to the e-pub versions of my novels (initially formatted for me by third parties). I'm finding it comparatively easy to use, but having problems with two specific operations:
(1) If I insert a couple of additional paragraphs (for example, lines of dialogue), it's giving double spacing, even although I used exactly the same HTML coding for each line as for the others
(2) Where I want to de-italicise (or italicise) a short section of a paragraph, using the <i>......<i> formula, it's applying that to not only the whole of that paragraph, but (as far as I can see) the whole of the section from that point onwards.
Any tips very, very welcome!

[Toxaris]

Are you adding additional paragraphs in an existing file or are you adding a new file? If the latter, don't forget to add/link the stylesheet to file.

The second one is easier. You are using <i>...<i> instead of <i>...</i>. You used two opening tags instead of one open and one close.

[theducks]

The first problem may be similar; failure to use a closing tag </p> resulting in a default, non-style being applied