diff --git a/pkgs/applications/networking/browsers/firefox/default.nix b/pkgs/applications/networking/browsers/firefox/default.nix
index 5ce5acde83f..2e164c08052 100644
--- a/pkgs/applications/networking/browsers/firefox/default.nix
+++ b/pkgs/applications/networking/browsers/firefox/default.nix
@@ -31,6 +31,7 @@ stdenv.mkDerivation {
     "--enable-xft"
     "--disable-freetype2"
     "--enable-svg"
+    "--enable-canvas"
     "--enable-strip"
     "--enable-default-toolkit=gtk2"
     "--with-system-jpeg"
@@ -43,4 +44,6 @@ stdenv.mkDerivation {
   meta = {
     description = "Mozilla Firefox - the browser, reloaded";
   };
+
+  passthru = {inherit gtk;};
 }
diff --git a/pkgs/applications/networking/mailreaders/thunderbird/default.nix b/pkgs/applications/networking/mailreaders/thunderbird/default.nix
index acccca4d7cf..d0960a45211 100644
--- a/pkgs/applications/networking/mailreaders/thunderbird/default.nix
+++ b/pkgs/applications/networking/mailreaders/thunderbird/default.nix
@@ -2,7 +2,7 @@
 , libjpeg, libpng, zlib, cairo
 
 , # If you want the resulting program to call itself "Thunderbird"
-  # instead of "Deer Park", enable this option.  However, those
+  # instead of "Mail", enable this option.  However, those
   # binaries may not be distributed without permission from the
   # Mozilla Foundation, see
   # http://www.mozilla.org/foundation/trademarks/.
@@ -32,6 +32,7 @@ stdenv.mkDerivation {
     "--enable-xft"
     "--disable-freetype2"
     "--enable-svg"
+    "--enable-canvas"
     "--enable-strip"
     "--enable-default-toolkit=gtk2"
     "--with-system-jpeg"