I have a "shell" that started life in Flash CS3 (Flash 9, AS3) that has been since used with CS4 and now CS5. It creates TextFields in ActionScript for display (reading the content of those fields from XML). The text fields are either Myriad Pro Regular or Myriad Pro Semibold, both are embedded in the SWF from the Library (any given text field will only use one of those fonts) and using Advanced anti-aliasing. Once a FLA goes into CS5 is still has the same problem when saved back into CS4.
The problem is the spacing between letters are now quite random, and the width of each text field is too wide (by about 10%). Changing the letterSpacing property (to something negative) makes this more noticeable. I read on here about Font.registerFont(MyriadPro) but that doesn't seem to be doing anything.
Does anyone know how to make CS5 behave like previous versions of Flash? I'm using Flash Professional on Snow Leopard (as part of CS5 Web Premium).