diff --git a/src/_h5ai/client/js/inc/ext/preview-img.js b/src/_h5ai/client/js/inc/ext/preview-img.js
index a9dc5a4a..d118a95e 100644
--- a/src/_h5ai/client/js/inc/ext/preview-img.js
+++ b/src/_h5ai/client/js/inc/ext/preview-img.js
@@ -3,7 +3,7 @@ modulejs.define('ext/preview-img', ['_', '$', 'core/settings', 'core/event', 'ex
 
 	var settings = _.extend({
 			enabled: false,
-			types: ['bmp', 'gif', 'ico', 'image', 'jpg', 'png', 'tiff']
+			types: []
 		}, allsettings['preview-img']),
 
 		preloadImg = function (src, callback) {
diff --git a/src/_h5ai/client/js/inc/ext/preview-txt.js b/src/_h5ai/client/js/inc/ext/preview-txt.js
index ef5fcf12..a6a85a2c 100644
--- a/src/_h5ai/client/js/inc/ext/preview-txt.js
+++ b/src/_h5ai/client/js/inc/ext/preview-txt.js
@@ -3,29 +3,7 @@ modulejs.define('ext/preview-txt', ['_', '$', 'core/settings', 'core/event', 'ex
 
 	var settings = _.extend({
 			enabled: false,
-			types: {
-				authors: 'plain',
-				copying: 'plain',
-				c: 'c',
-				cpp: 'cpp',
-				css: 'css',
-				h: 'c',
-				hpp: 'cpp',
-				install: 'plain',
-				log: 'plain',
-				java: 'java',
-				makefile: 'xml',
-				markdown: 'plain',
-				// php: 'php',
-				python: 'python',
-				readme: 'plain',
-				rb: 'ruby',
-				rtf: 'plain',
-				script: 'shell',
-				text: 'plain',
-				js: 'js',
-				xml: 'xml'
-			}
+			types: {}
 		}, allsettings['preview-txt']),
 
 		templateText = '<pre id="pv-txt-text" class="highlighted"/>',
@@ -142,7 +120,15 @@ modulejs.define('ext/preview-txt', ['_', '$', 'core/settings', 'core/event', 'ex
 
 							var $text;
 
-							if (currentItem.type === 'markdown') {
+							if (settings.types[currentItem.type] === 'none') {
+
+								$text = $(templateMarkdown).text(textContent);
+
+							} else if (settings.types[currentItem.type] === 'fixed') {
+
+								$text = $(templateText).text(textContent);
+
+							} else if (settings.types[currentItem.type] === 'markdown') {
 
 								$text = $(templateMarkdown).text(textContent);
 
diff --git a/src/_h5ai/conf/options.json b/src/_h5ai/conf/options.json
index 06562ed7..3f037a41 100644
--- a/src/_h5ai/conf/options.json
+++ b/src/_h5ai/conf/options.json
@@ -214,38 +214,41 @@ Options
 
 	/*
 	Show text file preview on click.
-	"types" maps file types to SyntaxHighligher brushes. Special case: "markdown" will
-	be rendered as HTML.
-
+	"types" maps file types to SyntaxHighligher brushes.
 	For available brushes see http://alexgorbatchev.com/SyntaxHighlighter/manual/brushes/
 
+	Additional type are:
+	 - "markdown" to render Markdown text
+	 - "none" for floating text
+	 - "fixed" for fixed width text
+
 	- types: maps types to brushes
 	*/
 	"preview-txt": {
 		"enabled": true,
 		"types": {
-			"authors": "plain",
-			"copying": "plain",
+			"authors": "fixed",
+			"copying": "fixed",
 			"c": "c",
 			"cpp": "cpp",
 			"css": "css",
 			"diff": "diff",
 			"h": "c",
 			"hpp": "cpp",
-			"install": "plain",
-			"log": "plain",
+			"install": "fixed",
+			"log": "fixed",
 			"java": "java",
 			"js": "js",
 			"json": "js",
 			"makefile": "xml",
-			"markdown": "plain",
+			"markdown": "markdown",
 			// "php": "php",
 			"python": "python",
-			"readme": "plain",
+			"readme": "fixed",
 			"rb": "ruby",
-			"rtf": "plain",
+			"rtf": "fixed",
 			"script": "shell",
-			"text": "plain",
+			"text": "fixed",
 			"xml": "xml"
 		}
 	},