diff --git a/koha-tmpl/intranet-tmpl/lib/koha/cateditor/marc-mode.js b/koha-tmpl/intranet-tmpl/lib/koha/cateditor/marc-mode.js
index 511a2bad84..8b67815980 100644
--- a/koha-tmpl/intranet-tmpl/lib/koha/cateditor/marc-mode.js
+++ b/koha-tmpl/intranet-tmpl/lib/koha/cateditor/marc-mode.js
@@ -130,6 +130,8 @@ CodeMirror.defineMode( 'marc', function( config, modeConfig ) {
                     // matching.
                     if ( stream.match( /[ \t]+$/ ) ) {
                         return 'end-space';
+                    } else if ( stream.match( /\s{2,}/ ) ) {
+                        return 'double-space';
                     } else if ( stream.match( /[^ \t‡]+/ ) || stream.match( /[ \t]+/ ) ) {
                         return;
                     }
@@ -156,6 +158,8 @@ CodeMirror.defineMode( 'marc', function( config, modeConfig ) {
                 // Match space at end of line
                 if ( stream.match( /[ \t]+$/ ) ) {
                     return 'end-space';
+                } else if ( stream.match( /\s{2,}/ ) ) {
+                    return 'double-space';
                 } else {
                     stream.match( /[ \t]+/ );
                 }
diff --git a/koha-tmpl/intranet-tmpl/prog/css/cateditor.css b/koha-tmpl/intranet-tmpl/prog/css/cateditor.css
index 277a1b1aa6..ba7de2e5b2 100644
--- a/koha-tmpl/intranet-tmpl/prog/css/cateditor.css
+++ b/koha-tmpl/intranet-tmpl/prog/css/cateditor.css
@@ -106,6 +106,10 @@ body {
     background-color: #DDDDBB;
 }
 
+.cm-double-space {
+    border-bottom: 2px dotted #CC3333;
+}
+
 #editor .modified-line-gutter {
     width: 10px;
 }