When a Rally user clicks the hyperlink button in a rich text field such as Description, or Notes, the hyperlink popup does not allow the user to add a "Display Text" which describes the destination of the hyperlink. This functionality was available prior to the new version of the editor.
Release : SAAS
In order to create a hyperlink with a custom description, you may now perform the following steps:
First, enter the text that you want to become a hyperlink
Highlight the text and then click the hyperlink button
Next, enter the URL that you want this text to link to and click the check mark
At that point, you should have a clickable hyperlink in your rich text field.