Added clearfix to box elements

build/less/boxes.less

@@ -164,10 +164,15 @@
 
 }
 
-//Box header
-.box-header {
-  //Add top left and top right border radius
+//Add clearfix to header, body and footer
+.box-header,
+.box-body,
+.box-footer {
   .clearfix();
+}
+
+//Box header
+.box-header {  
   color: #444;
   display: block;
   padding: @box-padding;

dist/css/AdminLTE.css

@@ -1571,20 +1571,26 @@ a:focus {
 .box .overlay.dark {
   background: rgba(0, 0, 0, 0.5);
 }
-.box-header {
-  color: #444;
-  display: block;
-  padding: 10px;
-  position: relative;
-}
 .box-header:before,
-.box-header:after {
+.box-body:before,
+.box-footer:before,
+.box-header:after,
+.box-body:after,
+.box-footer:after {
   content: " ";
   display: table;
 }
-.box-header:after {
+.box-header:after,
+.box-body:after,
+.box-footer:after {
   clear: both;
 }
+.box-header {
+  color: #444;
+  display: block;
+  padding: 10px;
+  position: relative;
+}
 .box-header.with-border {
   border-bottom: 1px solid #f4f4f4;
 }