Initial patch to make Firefox swap tabs on Ctrl+Shift+PgUp/PgDn (later updated, fixed and merged upstream!)

firefox_tab_reordering.patch

Ctrl+Shift+PageUp/Down reorder tabs (try #3, this one works and seems to be in the right place)
    
https://bugzilla.mozilla.org/show_bug.cgi?id=702960

diff -r d2fbc67f69f5 browser/base/content/tabbrowser.xml
--- a/browser/base/content/tabbrowser.xml	Fri Nov 30 13:51:45 2012 +0000
+++ b/browser/base/content/tabbrowser.xml	Mon Dec 03 14:35:29 2012 +0200
@@ -2504,6 +2504,25 @@
             return;
           }
 
+          switch (aEvent.keyCode) {
+            case aEvent.DOM_VK_PAGE_UP:
+              if (aEvent.ctrlKey && aEvent.shiftKey && !aEvent.altKey && !aEvent.metaKey) {
+                  this.moveTabBackward();
+                  aEvent.stopPropagation();
+                  aEvent.preventDefault();
+                  return;
+                }
+              break;
+            case aEvent.DOM_VK_PAGE_DOWN:
+              if (aEvent.ctrlKey && aEvent.shiftKey && !aEvent.altKey && !aEvent.metaKey) {
+                  this.moveTabForward();
+                  aEvent.stopPropagation();
+                  aEvent.preventDefault();
+                  return;
+                }
+              break;
+          }
+
           if (aEvent.altKey)
             return;
 

Continued via attachments on the original mozilla bug, and then (when it was closed as a duplicate), on https://bugzilla.mozilla.org/show_bug.cgi?id=364845