Interrupt 4 on a Leonardo

I know this forum is for the Due, but I don't know where to report problems with the IDE itself.

I'm using a Leonardo board and I noticed when I use version 1.5.2, and try the test code on the attachInterrupt web page (and changing the interrupt to 4 instead of 0), it doesn't work. The sketch compiles and uploads fine, however it doesn't work.

If I use version 1.0.5, it works and the interrupt does what it's supposed to do.

I realize 1.5.x is primarily meant for Due support, but if it's meant to some day replace the 1.0.x version, backwards compatibility needs to work. So I'd file this under bugs.