added overlay feature as suggested in issue #355

build/less/boxes.less

@@ -30,7 +30,7 @@
   &.box-default {
     border-top-color: @gray;
   }
-  
+
   // collapsed mode
   &.collapsed-box {
     .box-body,
@@ -38,7 +38,7 @@
       display: none;
     }
   }
-  
+
   .nav-stacked {
     > li {
       border-bottom: 1px solid @box-border-color;
@@ -74,7 +74,7 @@
       .btn.btn-default {
         background: transparent;
       }
-      .btn, 
+      .btn,
       a {
         &:hover {
           background: rgba(0,0,0,0.1)!important;
@@ -105,7 +105,7 @@
     > .box-header > .box-tools .btn {
       border: 0;
       box-shadow: none;
-    }    
+    }
 
     // Fix font color for tiles
     &[class*='bg'] {
@@ -132,7 +132,10 @@
     font-size: 12px;
     margin-bottom: 0.3em;
   }
+}
 
+.box,
+.overlay-wrapper {
   // Box overlay for LOADING STATE effect
   > .overlay,
   > .loading-img {
@@ -161,7 +164,6 @@
   .overlay.dark {
     background: rgba(0, 0, 0, 0.5);
   }
-
 }
 
 //Add clearfix to header, body and footer
@@ -172,7 +174,7 @@
 }
 
 //Box header
-.box-header {  
+.box-header {
   color: #444;
   display: block;
   padding: @box-padding;
@@ -244,7 +246,7 @@
   // Tables within the box body
   > .table {
     margin-bottom: 0;
-  }    
+  }
 
   // Calendar within the box body
   .fc {

dist/css/AdminLTE.css

@@ -1641,19 +1641,23 @@ a:focus {
   margin-bottom: 0.3em;
 }
 .box > .overlay,
-.box > .loading-img {
+.overlay-wrapper > .overlay,
+.box > .loading-img,
+.overlay-wrapper > .loading-img {
   position: absolute;
   top: 0;
   left: 0;
   width: 100%;
   height: 100%;
 }
-.box .overlay {
+.box .overlay,
+.overlay-wrapper .overlay {
   z-index: 50;
   background: rgba(255, 255, 255, 0.7);
   border-radius: 3px;
 }
-.box .overlay > .fa {
+.box .overlay > .fa,
+.overlay-wrapper .overlay > .fa {
   position: absolute;
   top: 50%;
   left: 50%;
@@ -1662,7 +1666,8 @@ a:focus {
   color: #000;
   font-size: 30px;
 }
-.box .overlay.dark {
+.box .overlay.dark,
+.overlay-wrapper .overlay.dark {
   background: rgba(0, 0, 0, 0.5);
 }
 .box-header:before,