app/main.js

@@ -193,6 +193,9 @@ function quitNow() {
   app.quit();
 }
 
+if (process.platform != 'linux') {
+  // On Linux, this is always returning true due to an Electron bug,
+  // so for now we just don't support single-instance apps on Linux.
   const isSecondaryInstance = app.makeSingleInstance((argv) => {
     if (win) {
       if (win.isMinimized()) {
@@ -212,6 +215,7 @@ if (isSecondaryInstance) { // We're not in the original process, so quit
     quitNow();
     return;
   }
+}
 
 app.on('ready', function(){
   launchDaemonIfNotRunning();