Turning off lights stops my HUD being transparent

My app is extending BaseSimpleGame.  The only way I can turn off the lights without removing the transparency of my HUD is by pressing "L" in game.  If I turn them off in the code during the startup (or even edit BaseSimpleGame so that the lights are never even turned on) my HUD stops being transparent.

Can anyone help please?

Thank in advance.

Did you do setLightCombineMode(LightCombineMode.Off) on the HUD elements?

No.  I tried adding it explicitly (with different values) but it made no difference.