Currently Qt4 uses " ", " "; Tk sets "tk", "Tk", GTK3 uses sys.argv[1]. I think using either matplotlib everywhere, or matplotlib-$backend, is fine. Can you look into whether this can easily be done with the other backends?

I had a short look at qt4 but didn't see the location where this is set. Can you give me a hint on the relevant source parts for the other backends?

Well, I don't know either :-)

I think I have found all relevant locations and updated the PR accordingly.

Right now (with this PR) some backends use "matplotlib", "Matplotlib" and others use "matplotlib", "matplotlib". Can you check how easy to keep this uniform across backends? (either way is fine)

There's also the wxagg backend but a quick googling suggests it can't set WM_CLASS (not sure though).

I tried, but I think not all GUI toolkits give access to control this completely.

No worries.

There is also the native osx backend, but unless you have a mac that one is hard to work on.

Is there anything like WM_CLASS for cocoa applications?

Not sure. There is also the 'gtk' backend (which is different than the gtk3 backend).

I have updated the commit to include the old and broken gtk backend. For wx I couldn't find any public API that allows setting the WM_CLASS.

@languitar As far as I know the GTK(2) backend should be working and not broken, but quite difficult to install (that is the GTKAgg and GTKCairo variants, the GDK variant is deprecated and possibly broken)

The backend that I touched (backend_gtk.py) issued a deprecation message when I executed it. That's what I was referring to.

👍

One last picking thing, we have settled on the convention of capitalizing Matplotlib in text, should we use that here too? I am leaning towards yes, but could be easily talked into either direction.

Ok thats fine. There are actually 2 subclasses of that backend that are not deprecated. The GTK backend uses GDK to do the actual drawing (which is different from all other backends) but the GTKAgg and GTKCairo backends which uses Agg and Cairo and are subclassed of the GTK backend are not since they use more standard matplotlib renders

wx probably doesn't expose such an API (http://wxpython-users.1045709.n5.nabble.com/Setting-WM-CLASS-td3270267.html).

@tacaswell It should probably be "matplotlib", "Matplotlib" if you care about case: https://tronche.com/gui/x/icccm/sec-4.html
That means Matplotlib for Qt and Tk.

Updated accordingly, at least for the backends where this is possible.

@tacaswell this looks ready to go