User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5 Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.5) Gecko/20091130 Thunderbird/3.0 This is a regression observer after upgrade from some TB beta to current RC When full header view is selected blank space is shown instead of headers. Normal header view works as expected. The headers (and the reply buttons and all other content) follows after blank space and is accessible by scrolling the header area. Reproducible: Always Steps to Reproduce: 1. upgrade to thunderbird 3 RC 2. open a mail folder 3. select View->Headers->All Actual Results: no headers/reply buttons/nothing is shown in the header area Expected Results: reply buttons and part of the headers that fits in the remaining space is displayed

Do you observe the issue in safe-mode (http://kb.mozillazine.org/Safe_mode)? When you see the issue, are there any thing related in Tools -> Error console ?

Do you have a scroll bar? When you scroll down and/or to the right, do you see the headers and buttons? I suspect that's a dupe of bug 526918.