Wiki markup does not work/display in text field

Symptoms

Attachments, inline images, links, {quote} or {noformat} wiki markup does not work in the text field such as comments.

Causes & Resolution

If the description Wiki Renderer is not working properly, here are three basic thing that we need to check:

1. Make sure the add-on/plugin is enabled.

2. Check the Field Configuration to see if Wiki Renderer is selected (instead of Default Text Renderer).

3. Go to System > General Configuration > Internet Explorer MIME Sniffing Security Hole Workaround Policy and make sure "Work around Internet Explorer security hole" is selected.