Hi Frank,
Yes this can be used as regular I/O but there are certain conditions(see below)
You must navigate to
Settings -> Device and Pin Options -> Dual -Purpose Pins
Description
Specifies how the DCLK pin should be used when the device is operating in user mode after configuration is complete. Depending on the current device and configuration scheme, the DCLK pin can be reserved as a regular I/O pin, as a dedicated programming pin, or compiler configured. If this pin is reserved as a regular I/O pin, the DCLK pin can be used as an ordinary output pin after configuration. If the DCLK pin is only used to interface with external memory for configuration, the DCLK pin should be reserved as compiler configured.
Regards