Unable to drag file from SMB-share / FTP-server / SFTP-server / WebDAV-server / MTP-device and drop it to other applications (such as Firefox)

[Norbert]

#### Expected behaviour
Normally file-browser allows user to drag file from file-browser and drop it to other application (such as Firefox).

#### Actual behaviour
Current Caja version (1.12.7-1 as in Ubuntu 16.04 LTS) does not support dragging file from Caja to Firefox.

#### Steps to reproduce the behaviour
1. Open SMB share (or FTP-server, or SFTP-server, or WebDAV-server, or MTP-device) in Caja
2. Open Firefox, go to any filesharing/cloud-storage service with drag&drop functionality (such as Yandex Disk)
3a. Try to drag file from Caja to Firefox
3b. Navigate manually to gvfs mount location (/run/user/1000/gvfs/smb-share\:server\=server\,share\=public/) and try to drag from here.

Note: this bug is somewhat related to [my AskUbuntu question](https://askubuntu.com/questions/966670/how-to-open-gvfs-smb-cifs-mount-location-in-terminal-from-caja).

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: caja 1.12.7-1
ProcVersionSignature: Ubuntu 4.4.0-97.120-generic 4.4.87
Uname: Linux 4.4.0-97-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.10
Architecture: amd64
CurrentDesktop: MATE
Date: Sat Oct 28 00:03:47 2017
InstallationDate: Installed on 2014-02-07 (1357 days ago)
InstallationMedia: Ubuntu 12.04.4 LTS "Precise Pangolin" - Release amd64 (20140204)
SourcePackage: caja
UpgradeStatus: Upgraded to xenial on 2017-04-15 (194 days ago)

[Launchpad Janitor (janitor)]

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

[Norbert (nrbrtx)]

18.04 LTS with all updates, bug exists.

[Norbert (nrbrtx)]

Bug still exists in latest Ubuntu MATE 22.04 LTS.