For now, it's just a drag target like the delete zone. Once all apps
and the home screen support a selection mode, this (and delete) will
be implemented as buttons in the Contextual Action Bar.
Change-Id: I6bf43d03eefda672ea34c583a7021137da22b184
When dragging an app shortcut, it was possible that we'd show a red rectangle
around a cell occupied by a UserFolder. This shouldn't be possible -- as soon
as that cell becomes the target drop cell, the folder should start handling
the drag and drop events.
Change-Id: I1b7a8b1aa9aeb7e2f1bd51ce8d947c06455e988f
