@Enodoc either go with
Lua Code:
ZO_ColorDef.FromInterfaceColor(colorType, fieldValue)
Using the dot instead, or just use this instead, which I think is better
Lua Code:
ZO_ColorDef:New(GetInterfaceColor(colorType, fieldValue))
So for you that would be
Lua Code:
ZO_ColorDef:New(GetInterfaceColor(INTERFACE_COLOR_TYPE_KEEP_TOOLTIP,KEEP_TOOLTIP_COLOR_ACCESSIBLE))