why clicking a hyperlink in excel will generate an HTTP request with MSIE 7.0 in User Agent?

Our application would export an Excel containing hyperlink data. If clicking on the hyperlink, the browser will automatically lead to a specific page. I am using IE8 on Windows XP.

Now, I noticed below behaviors in Fiddler:

1. when clicking the hyperlink in Excel, the User Agent in HTTP request looks like below:

   User-Agent: Mozil开发者_如何学JAVAla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0;....

2. above step actually opens the login page. If I enter user credential and login, then the User Agent would be like below: User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0...

My doubt is: why MSIE 7.0 is used in Step 1, while I was using IE8.0? (I didn't enable Compatibility view during the testing)

I think this link answers my doubt. After I added below, MSIE 8.0 was used in user agent (when clicking hyperlink from excel)

[(HKEY_CURRENT_USER or HKEY_LOCAL_MACHINE)\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION] "excel.exe" = dword 8888