'NO MATCHING PARTIAL' is hidden under the navbar, unless <header.html> is printed before. It seems to be no problem moving its insertion frome <post.html> and <page.html> to <single.html>, so that it is always shown.

layouts/_default/single.html

@@ -9,6 +9,8 @@
 
     <div role="main" class="container main-content">
 
+      {{ partial "header.html" . }}
+	  
       {{ if eq .Type "post" }}
         {{ partial "post.html" . }}
       {{ else if eq .Type "page" }}

layouts/partials/page.html

@@ -1,5 +1,3 @@
-{{ partial "header.html" . }}
-
 <div class="container" role="main">
   <div class="row">
     <div class="col-lg-8 col-lg-offset-2 col-md-10 col-md-offset-1">

layouts/partials/post.html

@@ -1,5 +1,3 @@
-{{ partial "header.html" . }}
-
 <div class="container">
   <div class="row">
     <div class="col-lg-8 col-lg-offset-2 col-md-10 col-md-offset-1">