Restore submenu support

docs/assets/css/bootstrap.css

@@ -2685,8 +2685,10 @@ fieldset[disabled] .btn-link:focus {
   white-space: nowrap;
 }
 
-.dropdown-menu li > a:hover,
-.dropdown-menu li > a:focus {
+.dropdown-menu > li > a:hover,
+.dropdown-menu > li > a:focus,
+.dropdown-submenu:hover > a,
+.dropdown-submenu:focus > a {
   color: #ffffff;
   text-decoration: none;
   background-color: #357ebd;
@@ -2753,6 +2755,58 @@ fieldset[disabled] .btn-link:focus {
   margin-bottom: 1px;
 }
 
+.dropdown-submenu {
+  position: relative;
+}
+
+.dropdown-submenu > .dropdown-menu {
+  top: 0;
+  left: 100%;
+  margin-top: -6px;
+  margin-left: -1px;
+  border-top-left-radius: 0;
+}
+
+.dropdown-submenu:hover > .dropdown-menu {
+  display: block;
+}
+
+.dropup .dropdown-submenu > .dropdown-menu {
+  top: auto;
+  bottom: 0;
+  margin-top: 0;
+  margin-bottom: -2px;
+  border-bottom-left-radius: 0;
+}
+
+.dropdown-submenu > a:after {
+  display: block;
+  float: right;
+  width: 0;
+  height: 0;
+  margin-top: 5px;
+  margin-right: -10px;
+  border-color: transparent;
+  border-left-color: #cccccc;
+  border-style: solid;
+  border-width: 5px 0 5px 5px;
+  content: " ";
+}
+
+.dropdown-submenu:hover > a:after {
+  border-left-color: #ffffff;
+}
+
+.dropdown-submenu.pull-left {
+  float: none;
+}
+
+.dropdown-submenu.pull-left > .dropdown-menu {
+  left: -100%;
+  margin-left: 10px;
+  border-top-right-radius: 0;
+}
+
 .dropdown .dropdown-menu .nav-header {
   padding-right: 20px;
   padding-left: 20px;

docs/assets/css/docs.css

@@ -295,6 +295,20 @@ section > ul li {
   margin-right: auto;
 }
 
+/* Example dropdowns */
+.bs-docs-example > .dropdown > .dropdown-menu,
+.bs-docs-example-submenu > .pull-left > .dropup > .dropdown-menu,
+.bs-docs-example-submenu > .pull-left > .dropdown > .dropdown-menu {
+  position: static;
+  display: block;
+  margin-bottom: 5px;
+}
+.bs-docs-example-submenu {
+  min-height: 180px;
+}
+.bs-docs-example-submenu > .pull-left + .pull-left {
+  margin-left: 20px;
+}
 
 
 /* Example templates