Use the method App.saveAs in the grid plugin Export.

static/plugin_dbui/src/grid/plugin/Export.js

@@ -15,6 +15,13 @@ Ext.define('App.grid.plugin.Export', {
     alias: 'plugin.pGridExport',
     requires: 'Ext.form.action.StandardSubmit',
 
+    /**
+     * @cfg {String]
+     * The root to construct the filename when exporting data.
+     * The file name is built as root.ext where ext is csv, tex or pdf.
+     */
+    fileRoot: undefined,
+
     /**
      * @cfg {String}
      * The new line separator used in the CSV / LaTeX file.
@@ -151,9 +158,14 @@ Ext.define('App.grid.plugin.Export', {
         "use strict";
 
         var me = this,
-            data = me.getCmp().toCSV();
-
-        App.save("csv", data);
+            data = me.getCmp().toCSV(),
+            root = me.fileRoot;
+
+        if (root !== undefined) {
+            App.saveAs(root + ".csv", data);
+        } else {
+            App.save("csv", data);
+        }
     },
 
     /**
@@ -165,9 +177,14 @@ Ext.define('App.grid.plugin.Export', {
         "use strict";
 
         var me = this,
-            data = me.doLaTeX();
-
-        App.save("tex", data);
+            data = me.doLaTeX(),
+            root = me.fileRoot;
+
+        if (root !== undefined) {
+            App.saveAs(root + ".tex", data);
+        } else {
+            App.save("tex", data);
+        }
     },
 
     /**

views/plugin_dbui/latex2pdf.pdf

@@ -2,6 +2,7 @@
 
     try:
         response.headers['Content-Type']='application/pdf'
+        response.headers['Content-Disposition']='attachment;filename="latex2pdf.pdf"'
         response.write(data, escape=False)
 
     except:

views/reports/report_4.html

@@ -45,7 +45,9 @@
 
     // instantiate the grid
     Ext.create('App.grid.Panel', {
-        plugins: ['pGridExport'],
+        plugins: [{
+            fileRoot: "report_4",
+            ptype: "pGridExport"}],
         store: cfgStore,
         columns: [
             {text: "Controller", dataIndex: 'controller', flex: 0.8},