Unable to drag URL from firefox and drop it to ~/Desktop or any other folder

[Norbert]

Steps to reproduce:
1. Have Ubuntu 21.04 installed
2. Open Firefox, enable Bookmarks Toolbar
3. Bookmark some page in it to bookmarks toolbar
4. Open Nautilus
5. Drag some bookmark from Bookmarks Toolbar and drop it to Nautilus window

Expected results:
* Nautilus accepted this drop, created desktop-file with URL, will allow to open the web-page on launch

Actual results:
* Nautilus shows the error window with text

    > Drag and drop is not supported.
    > An invalid drag type was used.

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: nautilus 1:3.38.2-1ubuntu1
ProcVersionSignature: Ubuntu 5.10.0-14.15-generic 5.10.11
Uname: Linux 5.10.0-14-generic x86_64
ApportVersion: 2.20.11-0ubuntu59
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: GNOME-Flashback:GNOME
Date: Sat Mar 6 11:57:50 2021
GsettingsChanges: b'org.gnome.nautilus.window-state' b'initial-size' b'(800, 505)'
SourcePackage: nautilus
UpgradeStatus: Upgraded to hirsute on 2021-01-25 (39 days ago)
usr_lib_nautilus:

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.