One-line staff, connecting barlines behavior

There are two separate issues, and I'll describe how to reproduce both.

Create a new score, and for instruments choose Snare Drum and Drumset, in that order. Double-click one of the barlines in the snare drum and drag it down to connect the barlines of the two staves, which is the expected behavior. But what also happens, unexpectedly, is that the barline now no longer extends above the single line of the snare drum staff. First error.

The second error arises immediately when you click on one of the now extended barlines. (This happens separately for each barline as you click on it.) It abruptly becomes shorter, and does not reach to the bottom of the five-line drumset staff. Furthermore, it can no longer be extended—the maximum value for "Span to" in the Inspector is apparently 4.

There's other little bits of weird behavior surrounding this issue, like the way the initial barline (at the beginning of the line) extends yet another unique distance, but I imagine these will go away when the headline issues are fixed.

When I discovered this, I thought, "Wow, this is the kind of ridiculous issue that I thought MuseScore had finally gotten past with 2.0! Guess not. This is as bad as some of those 1.3 issues."

But then I went and checked, and this issue did not exist in 1.3.

Now that I find myself wishing to connect some barlines in this fashion, I'm becoming quite desperate. This is no back-burner issue. I await to see how fast our brilliant coders can patch it.