texmaker - start new instance, documentation and logging missing

I have already started another TexMaker instance (in another virtual desktop).

Now I wanted to start a new instance. I.e. I started:

texmaker file.tex

Nothing happened at all. It immediately quit without any message. Also the other running TexMaker instance did not open the file. Just nothing.

What would I have expected:

- A new instance would start.
- At least some message like "another instance is already running".
- Maybe the other instance would open the file. Or maybe not. (I think it is fine, because almost always, I don't want to change the opened file in the other instance - almost always, I would want to open a new instance.)

Because nothing happened at all, I thought this would be a bug. Only some strace debugging indicated that it is probably behaving correctly.

The main bug report though:

I wondered how I could start a new instance. So I ran:

texmaker -h
texmaker --help

Again just nothing at all. No message.

Then I checked the man page. The man page doesn't tell anything about it.

In some forum post (https://tex.stackexchange.com/questions/126412/multiple-texmaker-windows), I read about the undocumented option `-n`. With that option, it works as intended:

texmaker -n file.tex

To summarize, that could be already like three individual bug reports:

- Man page should tell about `-n`.
- `texmaker -h` should always output something, even if another instance is running.
- `texmaker file.tex` should print some message if another instance is running.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: texmaker 5.0.3-1build5
ProcVersionSignature: Ubuntu 5.4.0-60.67-generic 5.4.78
Uname: Linux 5.4.0-60-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Fri Jan 29 10:46:59 2021
InstallationDate: Installed on 2020-05-01 (272 days ago)
InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
SourcePackage: texmaker
UpgradeStatus: No upgrade log present (probably fresh install)