Blurry text inside Symbols
I had this problem and I couldn’t find any solutions to it in any forum. After a while I figured out what the problem was. So I am posting it here for future reference.
Aliased text appear blurry when inside a symbol with more elements on it
Flash simulates the Aliased text using vectors. To do that Flash uses the top left corner of the symbol for doing the calculations. This top left corner is not necessarily the 0,0 coordinate. If the top left corner of another object in the symbol is sitting in a not whole x or y then Flash will calculate the Aliased text from there. Hence making the text looks blurry.
Make sure that the top left corner of the symbol is in an integer x and y coordinate. Inside the symbol place and object with the top left corner also in an integer x and y. A good way is to create an empty graphic and place it on 0,0. So it works as a registration point.