nicegrid: minor change to get unit to compile under 64-bit FPC.
nicegrid: minor change to get unit to compile under 64-bit FPC.

wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI