“Do you want to view only the webpage content that was delivered securely?”
If you open a secure web page inside Internet Explorer 8 (one that begins with https like the Gmail web site or even Amazon.com), you might see a security warning dialog that says - “This webpage contains content that will not be delivered using a secure HTTPS connection, which could compromise the security of the entire webpage.”
This is annoying because IE won’t remember your choice and the warning message will appear every time you visit that page or web site. It basically means that the secure (https) web page that you are trying to open contains images and other elements that are hosted on a non-https location. They call it mixed content.
If you would like to disable this security warning forever, go to Tools -> Internet Options and select the Security tab. Make sure the “Internet” zone is selected and then click the “Custom Level” button. Scroll-down the list of options and set the “Display mixed content” setting from “Prompt” to “Enable.”
The following video screencast explains the whole problem and the related solution in detail. The mixed content issue can only be fixed by the web developer, you are only suppressing the warning in the IE browser.