diff --git a/apps/zotonic_core/src/support/z_lib_include.erl b/apps/zotonic_core/src/support/z_lib_include.erl
index 47fe9f7778..003b4e0bb6 100644
--- a/apps/zotonic_core/src/support/z_lib_include.erl
+++ b/apps/zotonic_core/src/support/z_lib_include.erl
@@ -40,10 +40,10 @@ tag(Files, Context) ->
 
 %% @doc Generate the link and/or script tags for the given files.
 tag(Files, Args, Context) ->
-    case m_config:get_value(mod_development, libsep, Context) of
-        Empty when Empty == []; Empty == <<>>; Empty == undefined ->
+    case m_config:get_boolean(mod_development, libsep, Context) of
+        false ->
             tag1(Files, Args, Context);
-        _Other ->
+        true ->
             lists:foldr(fun(F, [Css,Js]) ->
                             [C,J] = tag1([F], Args, Context),
                             [[C|Css], [J|Js]]
@@ -65,10 +65,12 @@ url(Files, Args, Context) ->
 
 url_for(_F, [], _Ext, _Args, _Context) -> [];
 url_for(F, P, Ext, Args, Context) ->
-    [z_dispatcher:url_for(lib(Context), url_for_args(F, P, Ext, Args, Context), Context)].
+    [z_dispatcher:url_for(lib(Args, Context), url_for_args(F, P, Ext, Args, Context), Context)].
 
-lib(Context) ->
-    case z_convert:to_bool(m_site:get(minification_enabled, Context)) of
+lib(Args, Context) ->
+    case z_convert:to_bool( proplists:get_value(minify, Args, false))
+        orelse m_config:get_boolean(site, minification_enabled, Context)
+    of
         true -> lib_min;
         false -> lib
     end.
@@ -95,16 +97,60 @@ link_element(Css, CssPath, Args, Context) ->
            undefined -> [];
            TitleValue -> [<<" title=\"">>, TitleValue, $"]
            end,
-    MediaAttr = [<<" media=\"">>, proplists:get_value(media, Args, "all"), $"],
-    RelAttr = [<<" rel=\"">>, proplists:get_value(rel, Args, "stylesheet"), $"],
-    CssUrl = z_dispatcher:url_for(lib(Context), url_for_args(Css, CssPath, <<".css">>, Args, Context), Context),
-    iolist_to_binary([<<"<link href=\"">>, CssUrl, <<"\" type=\"text/css\"">>, MediaAttr, TitleAttr, RelAttr, $/, $>]).
+    Media = proplists:get_value(media, Args, <<"all">>),
+    Rel = proplists:get_value(rel, Args, <<"stylesheet">>),
+    CssUrl = z_dispatcher:url_for(
+        lib(Args, Context),
+        url_for_args(Css, CssPath, <<".css">>, Args, Context),
+        Context),
+    case z_convert:to_bool( proplists:get_value(async, Args, false)) of
+        true ->
+            iolist_to_binary([
+                <<"<link href=\"">>, CssUrl, <<"\" type=\"text/css\"">>,
+                   TitleAttr,
+                   <<" media=\"none\"">>,
+                   <<" onload=\"if(media!='">>, Media, <<"')media='">>, Media, <<"'\"">>,
+                   <<" rel=\"">>, Rel, $",
+                <<">">>,
+                <<"<noscript>">>,
+                    <<"<link href=\"">>, CssUrl, <<"\" type=\"text/css\"">>,
+                       TitleAttr,
+                       <<" media=\"">>, Media, $",
+                       <<" rel=\"">>, Rel, $",
+                    <<">">>,
+                <<"</noscript>">>
+
+            ]);
+        false ->
+            iolist_to_binary([
+                <<"<link href=\"">>, CssUrl, <<"\" type=\"text/css\"">>,
+                   TitleAttr,
+                   <<" media=\"">>, Media, $",
+                   <<" rel=\"">>, Rel, $",
+                <<">">>
+            ])
+    end.
 
 script_element(_Js, [], _Args, _Context) ->
     [];
 script_element(Js, JsPath, Args, Context) ->
-    JsUrl = z_dispatcher:url_for(lib(Context), url_for_args(Js, JsPath, <<".js">>, Args, Context), Context),
-    iolist_to_binary([<<"<script src=\"">>, JsUrl, <<"\" type=\"text/javascript\"></script>">>]).
+    JsUrl = z_dispatcher:url_for(
+        lib(Args, Context),
+        url_for_args(Js, JsPath, <<".js">>, Args, Context),
+        Context),
+    AsyncAttr = case z_convert:to_bool( proplists:get_value(async, Args, false)) of
+        true ->
+            <<" async ">>;
+        false ->
+            <<>>
+    end,
+    iolist_to_binary([
+            <<"<script src=\"">>, JsUrl, <<"\"">>,
+                AsyncAttr,
+                <<" type=\"text/javascript\"">>,
+            <<">">>,
+            <<"</script>">>
+        ]).
 
 url_for_args(Files, JoinedPath, Extension, Args, Context) ->
     AbsUrlArg = case proplists:get_value(absolute_url, Args, false) of
diff --git a/apps/zotonic_mod_base/priv/lib/js/apps/z.widgetmanager.js b/apps/zotonic_mod_base/priv/lib/js/apps/z.widgetmanager.js
index 7abdd870f3..8436c073a2 100644
--- a/apps/zotonic_mod_base/priv/lib/js/apps/z.widgetmanager.js
+++ b/apps/zotonic_mod_base/priv/lib/js/apps/z.widgetmanager.js
@@ -190,4 +190,20 @@ limitations under the License.
         return this;
     };
 
+    // Make jQuery UI optional
+    if (typeof $.ui === 'undefined') {
+        $.ui = {
+            dialog: {}
+        };
+    }
+
+    if (typeof $.widget !== 'function')
+    {
+        $.widget = function( widgetName ) {
+            let name = widgetName.replace(/^ui\./, '');
+            $.ui[name] = {
+            };
+        }
+    }
+
 })(jQuery);
diff --git a/apps/zotonic_mod_translation/priv/lib-src/Makefile b/apps/zotonic_mod_translation/priv/lib-src/Makefile
new file mode 100644
index 0000000000..4b72e7efe5
--- /dev/null
+++ b/apps/zotonic_mod_translation/priv/lib-src/Makefile
@@ -0,0 +1,3 @@
+
+../lib/css/mod_translation.css: mod_translation.less
+	lessc --include-path="../../../zotonic_mod_admin/priv/lib-src/zotonic-admin/less/" mod_translation.less ../lib/css/mod_translation.css
diff --git a/apps/zotonic_mod_translation/priv/lib/less/mod_translation.less b/apps/zotonic_mod_translation/priv/lib-src/mod_translation.less
similarity index 97%
rename from apps/zotonic_mod_translation/priv/lib/less/mod_translation.less
rename to apps/zotonic_mod_translation/priv/lib-src/mod_translation.less
index dfb7e745e2..0ebd47a804 100644
--- a/apps/zotonic_mod_translation/priv/lib/less/mod_translation.less
+++ b/apps/zotonic_mod_translation/priv/lib-src/mod_translation.less
@@ -1,4 +1,4 @@
-@import (reference) "../../../../zotonic_mod_admin/priv/lib/less/variables.less";
+@import (reference) "variables.less";
 
 .dropdown-menu {
     &.mod_translation_menu-has-icons {
diff --git a/apps/zotonic_mod_translation/priv/lib/less/config b/apps/zotonic_mod_translation/priv/lib/less/config
deleted file mode 100644
index 0b4a8ace50..0000000000
--- a/apps/zotonic_mod_translation/priv/lib/less/config
+++ /dev/null
@@ -1,8 +0,0 @@
-%% Less config for Zotonic's file watcher
-%% Params 'from' and 'to' are mandatory.
-%% Path values are local to this config file.
-[
-    {from, "mod_translation.less"},
-    {to, "../css/mod_translation.css"},
-    {params, "--include-path='../../../../zotonic_mod_admin/priv/lib/less'"}
-].
diff --git a/apps/zotonic_mod_translation/priv/lib/less/less_to_css b/apps/zotonic_mod_translation/priv/lib/less/less_to_css
deleted file mode 100755
index 52a0241371..0000000000
--- a/apps/zotonic_mod_translation/priv/lib/less/less_to_css
+++ /dev/null
@@ -1 +0,0 @@
-lessc --include-path="../../../../zotonic_mod_admin/priv/lib/less" mod_translation.less ../css/mod_translation.css
diff --git a/doc/ref/tags/tag_lib.rst b/doc/ref/tags/tag_lib.rst
index 2b2ea111bb..f1c8fe3213 100644
--- a/doc/ref/tags/tag_lib.rst
+++ b/doc/ref/tags/tag_lib.rst
@@ -29,13 +29,23 @@ Will output::
 
 The number at the end is the Unix modification time of the most recently changed file.
 
-The `lib` tag supports optional arguments to control the resulting html tag:
+The `lib` tag supports optional arguments to control the resulting html tag. The arguments are supplied
+after the list of files::
+
+  {% lib
+    "css/not-so-important-styles.css"
+    minify
+    async
+  %}
+
+
+Accepted arguments are:
 
 +-----------------+-------------+---------------------------------------------------------+
 |Option           |Default      |Description                                              |
 +=================+=============+=========================================================+
 |absolute_url     |false        |If true, prefix the generated URL with                   |
-|                 |             |"http://{hostname}/".                                    |
+|                 |             |"https://{hostname}/".                                   |
 +-----------------+-------------+---------------------------------------------------------+
 |title            |<empty>      |Specify a value for the title attribute of the link tag. |
 +-----------------+-------------+---------------------------------------------------------+
@@ -43,5 +53,10 @@ The `lib` tag supports optional arguments to control the resulting html tag:
 +-----------------+-------------+---------------------------------------------------------+
 |rel              |"stylesheet" |Specify value for the rel attribute of the link tag.     |
 +-----------------+-------------+---------------------------------------------------------+
+|minify           |             |Force minification use as ``{% lib ... minify %}``       |
++-----------------+-------------+---------------------------------------------------------+
+|async            |             |Load css or javascript asynchronously, use as            |
+|                 |             | ``{% lib ... async %}``                                 |
++-----------------+-------------+---------------------------------------------------------+
 
 .. seealso:: :ref:`mod_development`.