1.- This is not a bug report, so this post was moved to the proper section of the forum. Next time, please post in an appropriate section.
2.- What do you mean by "fog" ???... There's no fog in SL (but the ones possibly created with scripted objects using particles).
3.- The Cool VL Viewer implements the Classic Clouds (the closest thing to a "fog"). You can toggle them on/off and set their altitude via the Graphics tab of the Preferences floater. Note that Classic Clouds are not supported any more in SL in official viewers and other TPVs: the Cool VL Viewer is the only viewer to still provide them in SL (some other TPVs, such as Singularity, may still provide them in OpenSim only).
4.- The CTRL ALT SHIFT <-> toggle does exist in the Cool VL Viewer: it toggles the high altitude (Windlight) clouds. But you need to have the "Advanced" menu enabled to get it working (CTRL ALT D or "View" ->" Advanced Menu" to make the "Advanced" entry appear in the menu bar if you don't have it there already); the corresponding menu option is Advanced -> Rendering -> Types -> Clouds. Note also that this toggle won't work on non-QWERTY keyboards (because the "-" is not a shifted key on other keyboard layouts... Gotta love non-universal keyboard shortcuts...).
5.- A list of keyboard shortcuts is available in this forum,
here.