This is more of a problem for Firestorm since their phototools expose the shadow resolution outside debug settings and allow it to be configured on a per-graphics profile basis, but they will probably want me to report it even in the LL viewer.

Steps to reproduce:

* Have a fresh start of the viewer with shadows off and shadow resolution set to 1.0.

* Turn shadows on and observe that they are behaving normally, then turn them back off.

* Change shadow resolution to 2.0 (RenderShadowResolutionScale in debug). Turn shadows on: everything should still be okay.

* Change shadow resolution back to 1.0 without turning shadows off: they become a glitched mess, local projector lights stop working and further changes to the resolution have no effect.

* The glitch clears out by toggling shadows or even changing window size (e.g. control-alt-F1 to hide the menus and then bring them back).