1171 diff --git a/browser/components/preferences/advanced.js b/browser/components/preferences/advanced.js

  1172 --- a/browser/components/preferences/advanced.js

  1173 +++ b/browser/components/preferences/advanced.js

  1174 @@ -683,24 +683,42 @@ var gAdvancedPane = {

  1175      var brandBundle = document.getElementById("bundleBrand");

  1176      var shellBundle = document.getElementById("bundleShell");

  1177      var brandShortName = brandBundle.getString("brandShortName");

  1178      var promptTitle = shellBundle.getString("setDefaultBrowserTitle");

  1179      var promptMessage;

  1180      const IPS = Components.interfaces.nsIPromptService;

  1181      var psvc = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]

  1182                           .getService(IPS);

  1183 +

  1184 +    var env = Components.classes["@mozilla.org/process/environment;1"]

  1185 +                        .getService(Components.interfaces.nsIEnvironment);

  1186 +    var kde_session = 0;

  1187 +    if (env.get('KDE_FULL_SESSION') == "true")

  1188 +      kde_session = 1;

  1189 +

  1190      if (!shellSvc.isDefaultBrowser(false)) {

  1191        promptMessage = shellBundle.getFormattedString("setDefaultBrowserMessage", 

  1192                                                       [brandShortName]);

  1193        var rv = psvc.confirmEx(window, promptTitle, promptMessage, 

  1194                                IPS.STD_YES_NO_BUTTONS,

  1195                                null, null, null, null, { });

  1196 -      if (rv == 0)

  1197 +      if (rv == 0) {

  1198          shellSvc.setDefaultBrowser(true, false);

  1199 +        if (kde_session == 1) {

  1200 +          var shellObj = Components.classes["@mozilla.org/file/local;1"]

  1201 +                                   .createInstance(Components.interfaces.nsILocalFile);

  1202 +          shellObj.initWithPath("/usr/bin/kwriteconfig");

  1203 +          var process = Components.classes["@mozilla.org/process/util;1"]

  1204 +                                  .createInstance(Components.interfaces.nsIProcess);

  1205 +          process.init(shellObj);

  1206 +          var args = ["--file", "kdeglobals", "--group", "General", "--key", "BrowserApplication", "MozillaFirefox"];

  1207 +          process.run(false, args, args.length);

  1208 +        }

  1209 +      }

  1210      }

  1211      else {

  1212        promptMessage = shellBundle.getFormattedString("alreadyDefaultBrowser",

  1213                                                       [brandShortName]);

  1214        psvc.alert(window, promptTitle, promptMessage);

  1215      }

  1216    }

  1217  #endif