It must make the epub valid, sooner or later, so whenever it cleans it must check every tag, etc you put in there. This takes time. The other editors can be faster because they don't have to perform this checking. But you can get yourself in to a large size mess if you never check.
If it finds un/mis-matched tags, it will tell you where it fouind it was unmatched: at the end of the section. This is not a problem if you try to save with checking every once in a while, for you know where you were working and what you did. If you try to process all at the end of your work, it will take much longer to find where the error is.
|