MuseScore 3: Extending double (dashed etc.) bars with the mouse over the whole staff doesn't work.

If you want a continuous system bar line by lengthening it with the mouse, it won't work with double bar lines or newly set end bar lines (I haven't tried all other types). You can test this e.g. on a choir template by inserting other bar line types somewhere. Then you extend a normal bar line over the whole system. The other types remain non cross-system.
If you first lengthen the bar lines and then insert another bar line type, it works if the file is still brand-new. If you shorten it again, the other type stays long (and sometimes also changes the type). If you have already set a double bar line, lengthened the bar lines, shortened them again, deleted the double bar line and lengthened all of them again, the former double bar line will not be lengthened. Undoing (Ctrl+Z) in MuseScore 3 often doesn't really bring you back to the starting point (at this problem in any case), you have to reload the file for a "Reset" (This is probably an extra bug to report).

P.S.: There were some issues about the bar lines, but I didn't find exactly this problem among them. In the current dev version, the barline problem still exists.
OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 3.0.1.5145, revision: 5e42b27