The
Folding>Narrow to Fold command hides
all lines except those in the fold containing the caret.
When editing a file with folding, this can be used to "focus" in on a block
of code and create a less cluttered display. To
display the entire buffer again, invoke the
Folding>Expand All Folds command.
Folding>Narrow to Selection works in a similar manner,
except it hides all lines except those in the selection, rather than
those in the current fold.