Comment 4 for bug 1294320

In the linked branch, column view has the following behaviour:

Single-click mode:
                                  Single-click on folder opens it as a new column to the right.
                                  Double-click on folder opens it as the root column.

Double-click mode:
                                  Single-click on folder selects it.
                                  Double-click on folder opens it as a new column to the right.