Summary

Clicking an attached PDF to view renders slowly in IE11 and Safari, and much faster in Chrome and Firefox.  This seems to be related to the open bug report in PDF.js.  https://github.com/mozilla/pdf.js/issues/7431

Environment

Tested with the following browsers all from the same client machine, all accessing the same PDF / Confluence host instance.

Chrome v.58:   ~2 sec
Firefox v.24.0:  ~2 sec
IE 11:                ~20+ sec

I tested the client side using Win 2008 on one of our internal VM's which have Chrome, Firefox, and IE11 installed.  

The Confluence host side I tested a fresh install of Confluence 6.2.0 installed on my Mac.

Steps to Reproduce

To create the environment

1. Start Confluence (most recent version is fine.)
2. Create new or access an existing page
3. Attach the customer's PDF from the ticket (drag-and-drop to attach)
4. Save the page

To test rendering the PDF preview from different browsers

1. Navigate to the page that includes the embedded PDF
2. Click the PDF on the page when in View mode (not Edit mode)
3. Take note of the time taken to render and display the PDF

Expected Results

Same rendering time between all browsers

Actual Results

IE11 performs ~10x slower than Chrome or Firefox

Notes

• See attached video.

Workaround

• None.
• Wait for the page to render or use Chrome or Firefox which render the PDFs quickly.