New submission from Håkon Hægland: Hello. In order to group several instances of a given application under one icon in the desktop launcher (I am using Ubuntu 17.04) they must have the same appName property of the WM_CLASS string. For example, if I run emacs twice:
$ emacs & $ emacs & Both instances will show up under the Emacs icon in the desktop launchbar. The reason is that both instances have the same WM_CLASS string. We can check this string using $ xprop WM_CLASS and then click on the Emacs window. It then shows: WM_CLASS(STRING) = "emacs", "Emacs" Here "emacs" is the resource (appName), and "Emacs" is the className. Now, consider this program (my-tkapp.py): #! /usr/bin/env python import tkinter as tk root = tk.Tk(className='myTkApp') label = tk.Label(root, text="Hello World") label.pack() root.mainloop() If I run this program twice: $ my-tkapp.py & $ my-tkapp.py & and then run xprop to check the WM_CLASS property of both windows, the first window gives: WM_CLASS(STRING) = "myTkApp", "Mytkapp" whereas the second gives: WM_CLASS(STRING) = "myTkApp #2", "Mytkapp" Note that tkinter has added a #2 suffix to the app name property. This is not desired. It makes the window manager group the two windows under separate icons in the desktop launch bar. How can I keep the same appName property of the WM_CLASS string for different instances of my application? Note: This question was first asked at stackoverflow.com: https://stackoverflow.com/q/44795622/2173773 I tried to follow the source from the call: root = tkinter.Tk(className='myTkApp') but at 5 levels down on the stack I ended up inside TCL code, and I was not able to determine who was responsible for adding the "#2" suffix. However, a similar perl script gives the same behavior, so I suspect the problem is within the TCL TK code. Is there a way to change the WM_CLASS property of the window after the call to tkinter.Tk, but before entering mainloop() in order to work around the issue? After entering the mainloop(), I guess it is too late to do anything, since then the icon is already displayed in the window manager's launch bar. I am using Ubuntu 17.04 and Python version 3.6.1. Best regards, Håkon Hægland ---------- components: Tkinter messages: 297191 nosy: hakonhagland priority: normal severity: normal status: open title: tkinter.Tk() adds suffix to window class name when launching multiple instances type: behavior _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue30791> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
