ZBrushCentral

How do I invert a selection?

Just as one inverts masks, how do you invert a selection. I’ve tried CTRL + SHIFT + I, but that is a keybind to something else. I also tried doing CTRL + SHIFT + LMB and that didn’t do anything.

What I’m missing?

Reverse visibility - Shift+Ctrl+Click & Drag Background
http://www.pixologic.com/docs/index.php/ZBrush_3_Shortcuts#Partial_Mesh_Visibility

Thanks!