In Flash Professional CS4, I get \"migration issue\" warnings when I use mouse/keyboard input handler names such as onMouseDown, onKeyUp, etc., even though I have added event li
You can if you edit EnabledWarnings.xml in $Flash/$LOCALE/Configuration/Actionscript 3.0/EnabledWarnings.xml, where $Flash is the path to Flash inside your Applications/Program Files folder and $LOCALE is your language.
e.g.
/Applications/Adobe Flash CS4/en/Configuration/ActionScript 3.0/EnabledWarnings.xml
You will need to edit line 29, setting the enabled attribute to false for warning with id 1090:
EventHandler was not added as a listener.
Quick sidenote:
"Flash Builder (CS4)" is a confusing term. After Flex Builder 3, Flex Builder got renamed to Flash Builder, there is no Flash Builder CS4. The regular Flash IDE is known as Flash Professional/Flash Professional CS4, this was to avoid confusion between products with similar names: Flash Catalyst, Flash Builder(was Flex Builder), Flash Professional. Obviously it doesn't always work that great :)