The font i'm using does not have an italic style so i' ve made a paragraph style with 10% skew (Advanced Character Formats) and a numbered list.
This works, but when i add a Character Style with the same font and skew amount as a style for my numbered list then the numbers don't skew.
you just discovered a bug, I think. A bug that is longstanding.
Don't know if this ever worked with numbered lists.
Best do a bug report here:
Then come back and post the link so that we can vote for fixing this issue.
What could you do?
Find a substitution for the font that allows an italic style.
Or: Do your own font based on the skewed samples with the script IndyFont:
( ACP )
Wasn't there a very similar post a while ago that mentioned another option which Just Does Not Work™ in bullet/number lists? Can't recall what option it was – but it indeed also fell in the category of "why ever would such a simple thing stop working for what comes down to a character style applied to an auto-generated number??"
Using IndyFont to work around this is absolutely possible, but it should not be necessary – it's a bug.
Normally I'd recommend doing a trial run with a single-character font made with the free demo, but in this case, for a numbered list, it wouldn't amount to much and you'd still need the full version. (Which makes creating a Faux Italic version extremely easy as that is actually a built-in feature! See http://www.indiscripts.com/post/2014/11/what-s-new-in-indyfont-1-135)
it was Underline that is not working with the auto-numbering. Just tested that. Also Strike Through is not working. And there are some differences with property position in combination with baseline shift.
( ACP )