On OSX you can load either "legacy" version of OpenGL so 1.x/2.x or 3.x+. Not both. I found this out for Devisualization.Window. Most likely dgame by default is loading it in legacy mode.
Derelict GL is loading in legacy mode. You have to call 'reload' after creating a valid GL Context to update your OpenGL to the highest possible version. Maybe that doesn't work on Mac?