I just tried testing the Make date range components relative to panel calendar and it worked for me as it has in the past.
Here's a screenshot of sandbox data: I initially set the panel date range to Last Week (Mar 3 - Mar 9). I then used All Visits & Last Week date range on the metric. As expected, they both reflected the same values. Then I enabled the Make date range components relative to panel calendar. With that option in abled the last week date range, reflects the week prior to the start of the panel start date.
Then I enabled the Make date range components relative to panel calendar. With that option in abled the last week date range, reflects the week prior to the start of the panel start date.
Regarding the separate Right Click & Add Comparison Date range feature, without the relative date range option enabled, I was able to get the expected behavior.
Interestingly, once I enabled the feature, I couldn't get Right Click to work at all. Sounds like that is a bug.