nl_tokens: Find the top of an item relative to the content element and also the height .
pl_tokens: function refreshPosition ( item ) { // Find the top of an item by adding to the offsetHeight until we reach the  // content element. var current = item . element [ 0 ] ; item . top = 0 ; item . left = 0 ; item . right = 0 ; while ( current && current !== contentEl [ 0 ] ) { item . top += current . offsetTop ; item . left += current . offsetLeft ; if ( current . offsetParent ) { item . right += current . offsetParent . offsetWidth - current . offsetWidth - current . offsetLeft ; //Compute offsetRight } current = current . offsetParent ; } item . height = item . element . prop ( 'offsetHeight' ) ; var defaultVal = $mdUtil . floatingScrollbars ( ) ? '0' : undefined ; $mdUtil . bidi ( item . clone , 'margin-left' , item . left , defaultVal ) ; $mdUtil . bidi ( item . <mask> , 'margin-right' , defaultVal , item . right ) ; }