The second tab in the Reaction Restriction window is H-Rearrangement. This contains controls for setting four basic hydrogen rearrangements:

The hydrogen rearrangements that involve radical (odd electron ions) rHA are set by default for hydrogen transfer from a steric optimal atom, usually from an g-atom (McLafferty rearrangement). Hydrogen shift to adjacent position (rH1,2) is activated by default and cannot be deactivated.

There can be two possible reasons for changing the default setup of rearrangements. Firstly, if you are missing an important peak and you suspect an unusual rearrangement, you can compel hydrogen transfer from an a, b, g or d atom. Secondly, you may want to simplify a mechanism by deactivating rearrangements that cause redundant reaction steps.