Bug#887027: xdg-open: "Open destination folder" doesn't work with PCManFM

[Beta Version]

Package: xdg-utils
Version: 1.1.2-1
Severity: normal

Dear Maintainer,

In qBittorrent, when i click on "Open destination folder", nothing happens, while it should open a folder containing targeted file.
Terminal output:
/usr/bin/xdg-open: 912: /usr/bin/xdg-open: pcmanfm: not found

In Audacious audio player, instead of opening a folder with targeted file, it adds to playlist all files contained in that folder.
In Firefox, instead of opening a folder with targeted file, it starts Audacious and adds to playlist all files contained in that folder. 

pcmanfm-qt 0.12.0-5

-- Package-specific info:
Desktop environment: XDG_CURRENT_DESKTOP=LXQt

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.14.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=ru_RU.UTF-8, LC_CTYPE=ru_RU.UTF-8 (charmap=UTF-8), LANGUAGE=ru_RU:ru (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

xdg-utils depends on no packages.

Versions of packages xdg-utils recommends:
ii  libfile-mimeinfo-perl  0.28-1
ii  libnet-dbus-perl       1.1.0-4+b3
ii  libx11-protocol-perl   0.56-7
ii  x11-utils              7.7+3+b1
ii  x11-xserver-utils      7.7+7+b1

xdg-utils suggests no packages.

-- no debconf information