drag-selecting entries in 2nd or 3rd column makes them disappear

[Volny]

Here's a 3-column setup. As you can see, one of the artists is selected ("Bacewicz"). I've also selected 2 albums by ctrl-clicking or shift-clicking them. The bottom section filters to show 13 tracks:



However, if instead of ctrl-clicking or shift-click, I mouse drag the same 2 albums like this:




....then all the albums disappear from the album column. Note: the correct 13 tracks are still filtered down the bottom:




This bug isn't restricted to just the album column. It seems to happen to any column (I've tested in 3-, 4- and 5-column scenarios), as long as one of its 'parent' columns to the left has an item selected. So if "Bacewicz" wasn't selected in the above example, the bug wouldn't occur.

The bug doesn't happen if you drag from within the list of items, like this:



It only seems to happen if you drag from an empty area below the list:



It also doesn't happen if you drag from an empty area below, but you'd already selected (by clicking) one of the other items first (in this case, "Symphonies:):




windows version 10.0.19041
MM version: Gold 4.1.29.1910