Fedora bugzilla report here:
https://bugzilla.redhat.com/show_bug.cgi?id=1981967

Description of problem:
I was trying to bulk modify the genre attribute to several files.

Version-Release number of selected component:
picard-2.6.3-1.fc34

Additional info:
reporter: libreport-2.15.2
cgroup: 0::/user.slice/user-1000.slice/
user@1000.service
/app.slice/app-gnome-org.musicbrainz.Picard-17144.scope
cmdline: /usr/bin/python3 -s /usr/bin/picard
crash_function: value_edited
exception_type: IndexError
executable: /usr/bin/picard
interpreter: python3-3.9.6-1.fc34.x86_64
kernel: 5.12.15-300.fc34.x86_64
runlevel: N 5
type: Python3
uid: 1000

Truncated backtrace:
edittagdialog.py:273:value_edited:IndexError: list assignment index out of range

Traceback (most recent call last):
File "/usr/lib64/python3.9/site-packages/picard/ui/edittagdialog.py", line 273, in value_edited
self._modified_tag()[row] = value
IndexError: list assignment index out of range

Local variables in innermost frame:
self: <picard.ui.edittagdialog.EditTagDialog object at 0x7fb8d026fb80>
item: <PyQt5.QtWidgets.QListWidgetItem object at 0x7fb8d05a2ee0>
row: 1
value: ''