Merge pull request #247 from jgis/master

Force single app instance

Close #236

src/main.js

@@ -128,6 +128,17 @@ const trayImages = function() {
 }();
 var willAppQuit = false;
 
+// If there is already an instance, activate the window in the existing instace and quit this one
+if (app.makeSingleInstance((commandLine, workingDirectory) => {
+    // Someone tried to run a second instance, we should focus our window.
+    if (mainWindow) {
+      if (mainWindow.isMinimized()) mainWindow.restore();
+      else mainWindow.show();
+    }
+  })) {
+  app.quit()
+}
+
 function shouldShowTrayIcon() {
   if (process.platform === 'win32') {
     return true;