--- a/browser/extensions/mortar/host/common/ppapi-runtime.jsm
+++ b/browser/extensions/mortar/host/common/ppapi-runtime.jsm
@@ -1546,16 +1546,23 @@ class PPAPIInstance {
         type: "fullscreenChange",
         fullscreen: evt.data.fullscreen
       });
     });
 
     this.mm.addMessageListener("ppapipdf.js:hashchange", (evt) => {
       this.notifyHashChange(evt.data.url);
     });
+
+    this.mm.addMessageListener("ppapipdf.js:oncommand", (evt) => {
+      this.viewport.notify({
+        type: "command",
+        name: evt.data.name
+      });
+    });
   }
 
   notifyHashChange(url) {
     let location = new URL(url);
     if (location.hash) {
       this.viewport.notify({
         type: "hashChange",
         // substring(1) for getting rid of the first '#' character

--- a/browser/extensions/mortar/host/pdf/chrome/js/viewport.js
+++ b/browser/extensions/mortar/host/pdf/chrome/js/viewport.js
@@ -589,16 +589,31 @@ class Viewport {
   _handleHashChange(hash) {
     if (!this._documentDimensions) {
       this._initPosition = hash;
     } else {
       this._jumpToBookmark(hash);
     }
   }
 
+  _handleCommand(name) {
+    switch(name) {
+      case 'cmd_selectAll':
+        this._doAction({
+          type: 'selectAll'
+        });
+        break;
+      case 'cmd_copy':
+        this._doAction({
+          type: 'getSelectedText'
+        })
+        break;
+    }
+  }
+
   verifyPassword(password) {
     this._doAction({
       type: 'getPasswordComplete',
       password: password
     });
   }
 
   handleEvent(evt) {
@@ -609,22 +624,16 @@ class Viewport {
       case 'scroll':
         this._nextPosition = null;
         let position = this.getScrollOffset();
         if (this._runtimePosition.x != position.x ||
             this._runtimePosition.y != position.y) {
           this._refresh();
         }
         break;
-      case 'copy':
-        this._doAction({
-          type: 'getSelectedText'
-        })
-        evt.preventDefault();
-        break;
     }
   }
 
   invokeResize() {
     if (this._fullscreenStatus == 'changing') {
       return;
     }
     this._resize();
@@ -751,11 +760,14 @@ class Viewport {
       case 'getSelectedTextReply':
         // For now this message is used only by text copy so we handle just
         // that case.
         this._copyToClipboard(message.selectedText);
         break;
       case 'hashChange':
         this._handleHashChange(message.hash);
         break;
+      case 'command':
+        this._handleCommand(message.name);
+        break;
     }
   }
 }

--- a/browser/extensions/mortar/host/pdf/ppapi-content-sandbox.js
+++ b/browser/extensions/mortar/host/pdf/ppapi-content-sandbox.js
@@ -178,9 +178,40 @@ mm.addMessageListener("ppapipdf.js:save"
           .onDataAvailable(aRequest, aContext, aInputStream, aOffset, aCount);
       }
     };
 
     channel.asyncOpen2(listener);
   });
 });
 
+// This class is created to transfer global XUL commands event we needed.
+// The main reason we need to transfer it from sandbox side is that commands
+// triggered from menu bar targets only the outmost iframe (which is sandbox
+// itself) so we need to propagate it manually into the plugin's iframe.
+class CommandController {
+  constructor() {
+    this.SUPPORTED_COMMANDS = ['cmd_copy', 'cmd_selectAll'];
+    containerWindow.controllers.insertControllerAt(0, this);
+    containerWindow.addEventListener('unload', this.terminate.bind(this));
+  }
+
+  terminate() {
+    containerWindow.controllers.removeController(this);
+  }
+
+  supportsCommand(cmd) {
+    return this.SUPPORTED_COMMANDS.includes(cmd);
+  }
+
+  isCommandEnabled(cmd) {
+    return this.SUPPORTED_COMMANDS.includes(cmd);
+  }
+
+  doCommand(cmd) {
+    mm.sendAsyncMessage("ppapipdf.js:oncommand", {name: cmd});
+  }
+
+  onEvent(evt) {}
+};
+var commandController = new CommandController();
+
 mm.loadFrameScript("resource://ppapi.js/ppapi-instance.js", true);