Node assigned to IOBANK
The pins are grouped into I/O banks, each pin is part of one. The configuration of the I/O bank limits your freedom in the configuration of individual pins, as all the pins in the same bank share the same VCCIO (and possibly VREF). 

In other words, if you want to configure an I/O pin to a certain standard and the Pin Planner doesn't let you, it could be because the configuration of the associated I/O bank makes the pin configuration you want impossible.