Hide sidebar element on second level main menu elements && remove some special WP styling rules

app/assets/javascripts/specific/main_menu.js.erb

@@ -115,4 +115,8 @@ jQuery(document).ready(function($) {
     $(child).before(header);
   })
 
+  if($('.menu_root').hasClass('closed')) {
+      // TODO: Instead of hiding the sidebar move sidebar's contents to submenus and cache it.
+      $('#sidebar').toggleClass('-hidden', true);
+  }
 });

app/assets/stylesheets/layout/_base.sass

@@ -56,15 +56,6 @@ body
     overflow: visible
 
     #content-wrapper
-      &.hidden-navigation
-        margin-left: $main-menu-folded-width
-        width: calc(100% - #{$main-menu-folded-width})
-
-      &.nosidebar
-        padding: 0
-        width:    100%
-        margin-left: 0
-
       &.nomenus
         top: 0
         padding: 0

app/assets/stylesheets/layout/_main_menu.sass

@@ -59,7 +59,7 @@ $menu-item-line-height: 30px
       height: 100%
 
     .main-menu--children > li.partial
-      height: 100%
+      height: inherit
 
     .main-menu--children
       height: calc(100% - (#{$main-menu-item-height} + 10px)) // 10px spacing
@@ -314,9 +314,6 @@ a.main-menu--parent-node
   &.-hidden
     display: none
 
-  %absolute-layout-mode &
-    display: none
-
 .menu-wiki-pages-tree
   height: 100%
   overflow: auto
@@ -347,8 +344,6 @@ a.main-menu--parent-node
   vertical-align: middle
   z-index: 1
   cursor: col-resize
-  %absolute-layout-mode &
-    z-index: 100
   &:hover
     @include varprop(border-left-color, main-menu-resizer-color)
     .main-menu--navigation-toggler
@@ -395,8 +390,6 @@ a.main-menu--parent-node
     i:before
       padding-left: 0
       @include icon-mixin-arrow-left2
-  %absolute-layout-mode &
-    z-index: 100
 
 #main-menu ul ul.main-menu--children ul.pages-hierarchy
   .tree-menu--hierarchy-indicator

app/assets/stylesheets/layout/_main_menu_mobile.sass

@@ -36,9 +36,6 @@
     border: none
     box-shadow: 1px 1px 4px rgba(0, 0, 0, 0.15)
 
-    %absolute-layout-mode &
-      height: auto
-
   .hidden-navigation .main-menu
     display: none
 

app/assets/stylesheets/layout/work_packages/_full_view.sass

@@ -28,8 +28,6 @@
 
 body.controller-work_packages.action-show
 body.controller-work_packages.full-create
-  overflow-x: auto
-
   // Fix selenium scrolling the #content which shouldn't be possible
   // This appears to be caused by somehow setting the scrollTop to move to an element.
   #content-wrapper,

app/assets/stylesheets/layout/work_packages/_mobile.sass

@@ -50,15 +50,6 @@
         height: calc(100vh - #{$header-height})
 
         #content-wrapper
-          &.hidden-navigation
-            margin-left: 0
-            width: 100%
-
-          &.nosidebar
-            padding: 0
-            width:    100%
-            margin-left: 0
-
           &.nomenus
             top: 0
             padding: 0