464240 - File drop event is hidden from the extensions

Status: RESOLVED WORKSFORME

(Firefox :: Extension Compatibility, defect)

Description

[Igor Bazarny]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1) Gecko/20081007 Firefox/3.1b1
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1) Gecko/20081007 Firefox/3.1b1

On file drag and drop operation 'dragdrop' event is not received by the extension event handler attached to the main window. Only 'dragexit' event is seen by the extension. 
This breaks Google Toolbar integration with Google Documents--toolbar used to handle file drops for supported file types with upload to Google Docs. Plugging into later (content handling) stage will prevent user from uploading multiple files--default dnd handler discards all files except one. 

Reproducible: Always

Steps to Reproduce:
Test extension:

content/dnd-test.xul

<?xml version="1.0"?>
<!DOCTYPE overlay [
  <!ENTITY % globalDTD SYSTEM "chrome://global/locale/global.dtd"> %globalDTD;
]>

<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>

<overlay id="dndTestOverlay"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <window id="main-window">

    <script id="dnd-test">
      dump('dnd overlay loaded\n');
      function trace(event) {
        dump('event: ' + event.type + '\n');
      }
      addEventListener('dragenter', trace, true);
      addEventListener('dragover', trace, true);
      addEventListener('drag', trace, true);
      addEventListener('dragdrop', trace, true);
      addEventListener('dragexit', trace, true);
      addEventListener('dragend', trace, true);
    </script>
  </window>
</overlay>

chrome.manifest

overlay	chrome://browser/content/browser.xul	chrome://dnd-test/content/dnd-test.xul
content	dnd-test content/

install.rdf

<?xml version="1.0"?>

<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
     xmlns:em="http://www.mozilla.org/2004/em-rdf#">

  <Description about="urn:mozilla:install-manifest">
    <em:id>[e-mail]</em:id>
    <em:version>1.0</em:version>

    <!-- For Up-To-Date Documentation of this Format Please See: 
         http://www.mozilla.org/projects/firefox/extensions/packaging/extensions.html
         -->
    <em:targetApplication>
      <Description>
        <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
        <em:minVersion>2.0</em:minVersion>
        <em:maxVersion>3.*</em:maxVersion>
      </Description>
    </em:targetApplication>
    <em:name>Drag drop event test</em:name>
    <em:creator>Google Inc.</em:creator>
    <em:homepageURL>http://www.google.com/</em:homepageURL>
  </Description>
</RDF>


1. create .xpi from the above files
2. Install to Firefox 3.1
3. Enable dump, launch Firefox with console visible
4. Drag and drop file to the Firefox window
5. Check console, last event should be dragdrop and drag exit
Actual Results:  
No dragdrop event is seen, lase dragover event is followed by drag exit, action choice dialog (open, download) is shown for msoffice file types.

Expected Results:  
dragdrop event should be seen along with dragexit and action choice dialog

This doesn't happen in Firefox 2 and 3, only 3.1beta1 is affected

Comment 1

[Igor Bazarny]

Attachment: Test extension which prints drag events

Comment 2

[Neil Deakin]

This is because Firefox 3.1 supports the html5 drag/drop spec where the event is 'drop' not 'dragdrop'. 'dragdrop' is still supported but fired afterwards. The default content handlers in Firefox 3.1 have been changed to respond to 'drop' so the file you dropped will be handled and the dragdrop event won't be sent.

To fix this you could stop the 'drop' event, which will just be ignored on earlier versions of Firefox.

ondrop="event.stopPropagation()"

Comment 3

[Igor Bazarny]

(In reply to comment #2)
> This is because Firefox 3.1 supports the html5 drag/drop spec where the event
> is 'drop' not 'dragdrop'. 'dragdrop' is still supported but fired afterwards.
> The default content handlers in Firefox 3.1 have been changed to respond to
> 'drop' so the file you dropped will be handled and the dragdrop event won't be
> sent.
> 
> To fix this you could stop the 'drop' event, which will just be ignored on
> earlier versions of Firefox.
> 
> ondrop="event.stopPropagation()"

Yes, it solves my problem.