In my text I am using a lot of characters with accents, which should be easily composed in LaTeX. This seems to be dependent on specific fonts, at least when using xelatex in MiKTeX 2.9. In particular, in many fonts I cannot compose the accent over space \'{} and in some fonts (mostly professional, for example Garamond 3 LT Std, ITC Garamond Std, ...) the \v{C} and \v{c} characters. Instead of proper accented characters I'm getting some other characters or boxes with X.