BPU bug - tamper the run to completion does not tamper

[Rick]

BPU bootstrap.css correctly breaks on bootstrap. But when I "Break on Response", click the Raw tab, delete the contents, then run to completion, fiddler sends all of the CSS. You can verify it restores the CSS by deleting it, then click another tab , then click back the Raw tab, the CSS is restored. Furthermore, fiddler shows it sent the entire bootstrap.

"Choose Response" always works correctly (tampers the response).

If you enter a dozen newlines and some text (asdflj)  in the RAW tab, click another tab, then click RAW,  it will retain the tampering then display:

HTTP/1.1 200 OK
Content-Type: text/css
Last-Modified: Fri, 11 Oct 2013 00:27:46 GMT
Accept-Ranges: bytes
ETag: "0ad16b518c6ce1:0"
Vary: Accept-Encoding
Server: Microsoft-IIS/8.0
X-SourceFiles: =?UTF-8?B?Rjpccm1cTXZjTW92aWVSVE1cTXZjTW92aWVSVE1cTXZjTW92aWVcQ29udGVudFxib290c3RyYXAuY3Nz?=
X-Powered-By: ASP.NET
Date: Tue, 11 Mar 2014 03:07:08 GMT
Content-Length: 22






asdflj

I've repro'd this on two Win 8.1 boxes with Fiddler Web Debugger (v4.4.6.2)

[Eric Lawrence]

This is by-design.

If you go to the RAW tab and delete literally everything, including the HTTP headers, your response is no longer legal HTTP traffic and thus Fiddler ignores your modification. You can either manually delete just the body text, or you could use the TextView inspector (which doesn't show the headers) to delete the body text.

[Rick]

That's it!