I think I've finally pinpointed an Expression Web bug that has been driving me crazy.
I like to define multiple selectors all at once in stylesheets by separating them with commas. For example -- instead of defining the font color for each heading, like this:
h1 { color: red }
h2 { color: red }
...
... you can list the different selectors with commas to define the font color all at once, like this...
h1, h2, h3, h4, h5, h6 { color: red }
Well, I noticed that at some point (and I didn't know when until today), Expression Web would break out all the selectors into their own individual rules. So my simple CSS code would get turned into this:
h6 { color: red }
h5 { color: red }
h4 { color: red }
h3 { color: red }
h2 { color: red }
h1 { color: red }
I found this pretty aggravating, so today I finally sat down and worked hard to figure out what triggered the bug.
From my testing, it looks like if you copy content from one page in Expression Web and paste the content into another page, the bug will be triggered and your stylesheet reformatted. The unfortunate thing is that there is no way to "undo" the change -- you'd have to go back and manually type out your rules for them to be the way that they used to be.
I've put in a post at the Expression Web newsgroup and will keep you posted if there are any updates on this issue. If you've come across anything else, please post a comment!
In the meantime -- I've saved a copy of my properly formatted stylesheet as "backup.css," and use that to replace my stylesheet if I inadvertently reformat it by copying and pasting (which I do quite often!).