Speaking of groups and their center, there's an interesting quirk—bug?—when a group exists across multiple subfiles. When selecting such a group, you have to click on a part (in nested mode) that is actually in the group's top-level subfile, not the subfile of the current session. Otherwise, the selection center/editing pin will appear way off in the distance somewhere.
(This is not unique to 1.7, by the way.)
(This is not unique to 1.7, by the way.)