Use case 1:

If the unpublished variant is for branch A, but the channel manager shows branch B and a webmaster modifies experience page for branch B, then first the unpublished version of branch B must be checked out and stored as preview.

Use case 2: When unpublished variant is for A and has changes only in the hst:page, then when starting to edit branch B, the changes in the hst:page must be checked in as a new version in version history!! For this see below

ADDITION Note that it took me quite a long time while working on CMS-13159 to find out that when writing directly to the unpublished variant we MUST NOT forget to update

hippostdpubwf:lastModificationDate

Otherwise we will get problems with branches, since restoring a different version from version history only creates a new version for the unpublished variant IF it has an updated hippostdpubwf:lastModificationDate time, see

org.onehippo.repository.documentworkflow.DocumentHandle.isCurrentUnpublishedVersioned()

Conundrum

When in the Channel Manager a BRANCH is rendered from VERSION HISTORY, then all UUIDs will point to frozen nodes. When restoring the version to unpublished, are the UUIDs then maintained??? This might be a tough nut to crack. Hence raising the story points