PIC24 external interrupt INT1 problem (zijo)

PIC24FJ64GB002 compiles with XC16 ok but it never interrupts when triggered by stimulus switch on port RA1.If I set bit to IEC1 = 0x0010; then it goes to interrupt function.Did I miss something? AD1CON1 = 0x0f; //digital
TRISB = 0xF8;
TRISA = 0x..