diff --git a/CHANGELOG b/CHANGELOG
index 5b783e136..ee79237d0 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -3,6 +3,7 @@ CHANGELOG Roundcube Webmail
 
 - Fix regression in displaying contents of message/rfc822 parts (#1490606)
 - Fix handling of message/rfc822 attachments on replies and forwards (#1490607)
+- Fix PDF support detection in Firefox > 19 (#1490610)
 
 RELEASE 1.2-beta
 ----------------
diff --git a/program/js/app.js b/program/js/app.js
index 763736037..142432a32 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -8755,14 +8755,10 @@ function rcube_webmail()
     if (!this.env.browser_capabilities)
       this.env.browser_capabilities = {};
 
-    if (this.env.browser_capabilities.pdf === undefined)
-      this.env.browser_capabilities.pdf = this.pdf_support_check();
-
-    if (this.env.browser_capabilities.flash === undefined)
-      this.env.browser_capabilities.flash = this.flash_support_check();
-
-    if (this.env.browser_capabilities.tif === undefined)
-      this.tif_support_check();
+    $.each(['pdf', 'flash', 'tif'], function() {
+      if (ref.env.browser_capabilities[this] === undefined)
+        ref.env.browser_capabilities[this] = ref[this + '_support_check']();
+    });
   };
 
   // Returns browser capabilities string
@@ -8781,11 +8777,14 @@ function rcube_webmail()
 
   this.tif_support_check = function()
   {
-    var img = new Image();
+    window.setTimeout(function() {
+      var img = new Image();
+      img.onload = function() { ref.env.browser_capabilities.tif = 1; };
+      img.onerror = function() { ref.env.browser_capabilities.tif = 0; };
+      img.src = ref.assets_path('program/resources/blank.tif');
+    }, 10);
 
-    img.onload = function() { ref.env.browser_capabilities.tif = 1; };
-    img.onerror = function() { ref.env.browser_capabilities.tif = 0; };
-    img.src = this.assets_path('program/resources/blank.tif');
+    return 0;
   };
 
   this.pdf_support_check = function()
@@ -8821,6 +8820,14 @@ function rcube_webmail()
         return 1;
     }
 
+    window.setTimeout(function() {
+      $('<object>').css({position: 'absolute', left: '-10000px'})
+        .attr({data: ref.assets_path('program/resources/dummy.pdf'), width: 1, height: 1, type: 'application/pdf'})
+        .load(function() { ref.env.browser_capabilities.pdf = 1; })
+        .error(function() { ref.env.browser_capabilities.pdf = 0; })
+        .appendTo($('body'));
+      }, 10);
+
     return 0;
   };
 
diff --git a/program/resources/dummy.pdf b/program/resources/dummy.pdf
new file mode 100644
index 000000000..8c5ca5424
Binary files /dev/null and b/program/resources/dummy.pdf differ