Make sure that the min/max depth of the `PageOutline` is within the 1-6 range. Closes #2136.
Make sure that the min/max depth of the `PageOutline` is within the 1-6 range. Closes #2136.

git-svn-id: 0d96b0c1a6983ccc08b3732614f4d6bfcf9cbb42@2316 af82e41b-90c4-0310-8c96-b1721e28e2e2

rbaumg/trac,rbaumg/trac,rbaumg/trac,rbaumg/trac