I have download the Adobe Flex SDK 4.6, modified the DropDownController.as file, ran the ant script to generate the modified SDK.
I have created new Flex project with this modified SDK but still the old code is getting reflecting instead of the modified SDK.
What am I doing wrong.
(PS: I'm trying to avoid doing monkey patching)
I would think monkey patching is much easier.
If you are using RSLs, then your changes are not going to be in the official RSL and you will need to monkey patch.
If you are static linking the libraries then what you did should work although Flash Builder would require a restart as it might cache the old SWCs.
Restarting the Flash Builder worked!