A "key zone" is a range of keys, that plays a sample. All key zones together make up a "key map".
To create a new key zone, the following methods can be used:
Select "Split Key Zone" from the Edit or context menus.
This splits the currently selected key zone in the middle. The new zone is the upper half of the split, and is empty. The dividing point has a "handle" above it, see "Setting the Key Zone Range" below for a description.
By [Alt]-clicking at a point just above the key zone strip, a new empty key zone is created.
The point where you click becomes the lower limit (or boundary) for the original key zone, and the upper limit for the new key zone.