Gmail has a seemingly simple but actually powerful filtering system. The "Has the words" input field can be used for arbitrary queries . However, the one line input is very cramped when trying to filter multiple mailing lists at once. A textarea would be more appropriate. Initially, this seemed like a job for Greasemonkey . However, since the filter input form is created dynamically, it's hard to detect when it's visible without resorting to polling. Instead, it seemed easier to find the right node with a CSS selector like input[name="cf1_has"] . Then, XBL can be used to replace the input node with a textarea node (styled appropriately). All that's really necessary is to insert the following in userContent.css : @-moz-document domain( mail.google.com ) { input[name="cf1_has"] { display: none; -moz-binding: url( http://persistent.info/files/gmail-filter.xml#filter ); } } The XBL file is pretty straightforward (it didn't ...