Why is Sigil changing the font size?
 

I used Calibre to convert an lrf to epub. In doing so, the book ended up with a duplicate cover. So, I installed Sigil and deleted the second cover picture and page break, and saved it. I was surprised to see that in the resulting epub file, the text is smaller. Just to test, I opened the Calibre-created epub in Sigil and re-saved it without making any changes, and sure enough, the font size got smaller. Why is this happening? Also, what other changes are being made to the document when it passes through Sigil?

It is possible calibre is injecting some flow-specific CSS in each XHTML file that modifies the text size. Sigil currently removes flow-specific CSS on import (very long story).

Preservation of flow-specific CSS will be back in 0.2.0.

Valloric, thank you very much for contributions to the ebook community. Might you be able to give a ballpark guess as to when 0.2.0 will appear?

Ballpark guess? Two months. But that's a big ballpark. Could be a lot sooner, or a lot later. Depends completely on my university workload.

I have also noticed that if I am editing an imported ePub file and I delete a space between sentences it often changes the font of the sentence after the deleted space????

You probably had a span tag (with styles applied) wrapped around that sentence, and now you've merged the other sentence into that span tag. Naturally, the other sentence now has those same styles too.

Just to note, you can use the remove first image conversion option in calibre to remove duplicate covers.