Here is a hint from the Lollygaggers in SL:
This will add two quick-controls to the Firestorm QuickPreferences
Atmospheric Shaders -- as a fix for things not rezzing, toggle this.
Advanced Lighting -- for quick togging when going from RP zones to overlit clubs.
Make sure you have quick preferences as one of your buttons, then click it.
(It's the one that looks like the Phoenix logo)
Click the wrench at the bottom right corner of the QP panel.
Click the [+] next to the text box.
Type a new name in the box: Atmos Shaders
On the "Choose" dropdown find: WindLightUseAtmosShaders
Type: Checkbox (or Radio Button)
Repeat the above except:
Name: Adv. Lighting
Click the X in corner of the lower half to return to the normal QP view.
Note: Advanced. Lighting won't enable unless Atmospheric Shaders is also enabled.