In Lubuntu 19.04, a file does not open on double-click when vim is configured as default application for this filetype

[Mathieu]

# Steps to reproduce

After a fresh Lubuntu 19.04 installation in a virtual machine:
- create an empty file on the desktop,
- right-click on the file>Properties>General>Open With: Vim>OK,
- double click on the file.

# Expected results

Double-clicking on the file should open it in vim (terminal).

# Actual results

Nothing happens on double-click.

# Affected version

Lubuntu 19.04
pcmanfm-qt 0.14.1

# Additional notes

Note 1: if we select gVim or FeatherPad instead of vim as the default application to open the file, it opens.

Note 2: When the default application to open the file is set to vim, if instead of double-clicking on the file we right-click>Open With...>Vim, then it opens. So it looks like it is only when we double-click on the file that nothing happen.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: pcmanfm-qt 0.14.1-0ubuntu1
ProcVersionSignature: Ubuntu 5.0.0-13.14-generic 5.0.6
Uname: Linux 5.0.0-13-generic x86_64
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
CurrentDesktop: LXQt
Date: Thu May 2 21:52:52 2019
InstallationDate: Installed on 2019-05-02 (0 days ago)
InstallationMedia: Lubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
SourcePackage: pcmanfm-qt
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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

[Chris Guiver (guiverc)]

Thank you for reporting this bug to Ubuntu.

Ubuntu 19.04 (disco) reached end-of-life on January 23, 2020.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in.

[Launchpad Janitor (janitor)]

[Expired for pcmanfm-qt (Ubuntu) because there has been no activity for 60 days.]

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

Actually, I can confirm this in the latest daily.

If you kill pcmanfm-qt and run `pcmanfm-qt --desktop` on the background, on double click, you'll get the following:

sh: 1: exec: xterm: not found

I do notice that our configuration for file for libfm suggests lxterminal, so that's a problem that should probably be fixed, but fixing that doesn't solve the problem. I'm a little baffled.