How do I turn on the strict mode in Flash Builder 4?
--update
I found something about "Preferences -> Actionscript 3 Settings", but there is no such option in Flash Builder preferences.
How do I turn on the strict mode in Flash Builder 4?
--update
I found something about "Preferences -> Actionscript 3 Settings", but there is no such option in Flash Builder preferences.
Project->Properties->Flex Compiler->Enable strict type checking.
But it should be enabled by default.
Check that Build Automatically is selected, that could be causing your confusion. Or if you like it deselected, try a clean/build. You'll also have to be using it within your 'default' application somewhere (referring to it in the source) for it to find errors.