Hi,
As you know that the LPC1788 is a bit old, it was launched in 2013 year.
The GUI guider does not support the LPC1788, if you want to use GUI guider tools to develop graphic interface, I suggest you consider LPC54xxx including LPC54628, LPC54018 which have LCD interface and GUI guider supports the two chips.
Hope it can help you
BR
XiangJun Rong