sorry to be a PITA, modifying the NGUI library is not something I want to do, it means I need to redo the changes every time I upgrade the NGUI project (which has been a many times recently!), originally I thought would just extend the UITooltip interface ( ie. void ExtentedFunc(this UITooltip tooltip) { ... }) but I think this isn't possible with the singleton implementation. If mInstance was public, then I'd I could use extensions np.
thanks