绝对定位元素隐藏在select2容器边界内

Question

我希望我的绝对定位元素与类java.io.InputStream溢出select2容器的边界，但它似乎不起作用。

HTML：

.box

CSS：

<div>
  <img class='nasaLogo' src='https://s3-us-west-2.amazonaws.com/s.cdpn.io/4579/NASA_meatball.png'/>
  <span>Multi select with image using Select2</span>
</div>

<select style="width:300px" id="states" multiple="true">
  <option value=""></option>
  <optgroup label="Alaskan/Hawaiian Time Zone">
    <option value="AK">Alaska</option>
    <option value="HI">Hawaii</option>
  </optgroup>  
</select> 

JS：

@import "compass/css3";

#states{
  margin: 20px;
}

.box {
  position: absolute;
  width: 500px;
  height: 50px;
  background-color: red;
}

.nasaLogo{
  max-width: 24px;
}

.select2-container {
    margin: 0;
    position: relative;
    display: inline-block;
    /* inline-block for ie7 */
    zoom: 1;
    *display: inline;
    vertical-align: middle;
}

.select2-container,
.select2-drop,
.select2-search,
.select2-search input {
  /*
    Force border-box so that % widths fit the parent
    container without overlap because of margin/padding.
    More Info : https://www.quirksmode.org/css/box.html
  */
  -webkit-box-sizing: border-box; /* webkit */
     -moz-box-sizing: border-box; /* firefox */
          box-sizing: border-box; /* css3 */
}

.select2-container .select2-choice {
    display: block;
    height: 26px;
    padding: 0 0 0 8px;
    overflow: hidden;
    position: relative;

    border: 1px solid #aaa;
    white-space: nowrap;
    line-height: 26px;
    color: #444;
    text-decoration: none;

    border-radius: 4px;

    background-clip: padding-box;

    -webkit-touch-callout: none;
      -webkit-user-select: none;
         -moz-user-select: none;
          -ms-user-select: none;
              user-select: none;

    background-color: #fff;
    background-image: -webkit-gradient(linear, left bottom, left top, color-stop(0, #eee), color-stop(0.5, #fff));
    background-image: -webkit-linear-gradient(center bottom, #eee 0%, #fff 50%);
    background-image: -moz-linear-gradient(center bottom, #eee 0%, #fff 50%);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr = '#ffffff', endColorstr = '#eeeeee', GradientType = 0);
    background-image: linear-gradient(top, #fff 0%, #eee 50%);
}

.select2-container.select2-drop-above .select2-choice {
    border-bottom-color: #aaa;

    border-radius: 0 0 4px 4px;

    background-image: -webkit-gradient(linear, left bottom, left top, color-stop(0, #eee), color-stop(0.9, #fff));
    background-image: -webkit-linear-gradient(center bottom, #eee 0%, #fff 90%);
    background-image: -moz-linear-gradient(center bottom, #eee 0%, #fff 90%);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#eeeeee', GradientType=0);
    background-image: linear-gradient(top, #eee 0%, #fff 90%);
}

.select2-container.select2-allowclear .select2-choice .select2-chosen {
    margin-right: 42px;
}

.select2-container .select2-choice > .select2-chosen {
    margin-right: 26px;
    display: block;
    overflow: hidden;

    white-space: nowrap;

    text-overflow: ellipsis;
}

.select2-container .select2-choice abbr {
    display: none;
    width: 12px;
    height: 12px;
    position: absolute;
    right: 24px;
    top: 8px;

    font-size: 1px;
    text-decoration: none;

    border: 0;
    background: url('select2.png') right top no-repeat;
    cursor: pointer;
    outline: 0;
}

.select2-container.select2-allowclear .select2-choice abbr {
    display: inline-block;
}

.select2-container .select2-choice abbr:hover {
    background-position: right -11px;
    cursor: pointer;
}

.select2-drop-mask {
    border: 0;
    margin: 0;
    padding: 0;
    position: fixed;
    left: 0;
    top: 0;
    min-height: 100%;
    min-width: 100%;
    height: auto;
    width: auto;
    opacity: 0;
    z-index: 9998;
    /* styles required for IE to work */
    background-color: #fff;
    filter: alpha(opacity=0);
}

.select2-drop {
    width: 100%;
    margin-top: -1px;
    position: absolute;
    z-index: 9999;
    top: 100%;

    background: #fff;
    color: #000;
    border: 1px solid #aaa;
    border-top: 0;

    border-radius: 0 0 4px 4px;

    -webkit-box-shadow: 0 4px 5px rgba(0, 0, 0, .15);
            box-shadow: 0 4px 5px rgba(0, 0, 0, .15);
}

.select2-drop.select2-drop-above {
    margin-top: 1px;
    border-top: 1px solid #aaa;
    border-bottom: 0;

    border-radius: 4px 4px 0 0;

    -webkit-box-shadow: 0 -4px 5px rgba(0, 0, 0, .15);
            box-shadow: 0 -4px 5px rgba(0, 0, 0, .15);
}

.select2-drop-active {
    border: 1px solid #5897fb;
    border-top: none;
}

.select2-drop.select2-drop-above.select2-drop-active {
    border-top: 1px solid #5897fb;
}

.select2-drop-auto-width {
    border-top: 1px solid #aaa;
    width: auto;
}

.select2-drop-auto-width .select2-search {
    padding-top: 4px;
}

.select2-container .select2-choice .select2-arrow {
    display: inline-block;
    width: 18px;
    height: 100%;
    position: absolute;
    right: 0;
    top: 0;

    border-left: 1px solid #aaa;
    border-radius: 0 4px 4px 0;

    background-clip: padding-box;

    background: #ccc;
    background-image: -webkit-gradient(linear, left bottom, left top, color-stop(0, #ccc), color-stop(0.6, #eee));
    background-image: -webkit-linear-gradient(center bottom, #ccc 0%, #eee 60%);
    background-image: -moz-linear-gradient(center bottom, #ccc 0%, #eee 60%);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr = '#eeeeee', endColorstr = '#cccccc', GradientType = 0);
    background-image: linear-gradient(top, #ccc 0%, #eee 60%);
}

.select2-container .select2-choice .select2-arrow b {
    display: block;
    width: 100%;
    height: 100%;
    background: url('select2.png') no-repeat 0 1px;
}

.select2-search {
    display: inline-block;
    width: 100%;
    min-height: 26px;
    margin: 0;
    padding-left: 4px;
    padding-right: 4px;

    position: relative;
    z-index: 10000;

    white-space: nowrap;
}

.select2-search input {
    width: 100%;
    height: auto !important;
    min-height: 26px;
    padding: 4px 20px 4px 5px;
    margin: 0;

    outline: 0;
    font-family: sans-serif;
    font-size: 1em;

    border: 1px solid #aaa;
    border-radius: 0;

    -webkit-box-shadow: none;
            box-shadow: none;

    background: #fff url('select2.png') no-repeat 100% -22px;
    background: url('select2.png') no-repeat 100% -22px, -webkit-gradient(linear, left bottom, left top, color-stop(0.85, #fff), color-stop(0.99, #eee));
    background: url('select2.png') no-repeat 100% -22px, -webkit-linear-gradient(center bottom, #fff 85%, #eee 99%);
    background: url('select2.png') no-repeat 100% -22px, -moz-linear-gradient(center bottom, #fff 85%, #eee 99%);
    background: url('select2.png') no-repeat 100% -22px, linear-gradient(top, #fff 85%, #eee 99%);
}

.select2-drop.select2-drop-above .select2-search input {
    margin-top: 4px;
}

.select2-search input.select2-active {
    background: #fff url('select2-spinner.gif') no-repeat 100%;
    background: url('select2-spinner.gif') no-repeat 100%, -webkit-gradient(linear, left bottom, left top, color-stop(0.85, #fff), color-stop(0.99, #eee));
    background: url('select2-spinner.gif') no-repeat 100%, -webkit-linear-gradient(center bottom, #fff 85%, #eee 99%);
    background: url('select2-spinner.gif') no-repeat 100%, -moz-linear-gradient(center bottom, #fff 85%, #eee 99%);
    background: url('select2-spinner.gif') no-repeat 100%, linear-gradient(top, #fff 85%, #eee 99%);
}

.select2-container-active .select2-choice,
.select2-container-active .select2-choices {
    border: 1px solid #5897fb;
    outline: none;

    -webkit-box-shadow: 0 0 5px rgba(0, 0, 0, .3);
            box-shadow: 0 0 5px rgba(0, 0, 0, .3);
}

.select2-dropdown-open .select2-choice {
    border-bottom-color: transparent;
    -webkit-box-shadow: 0 1px 0 #fff inset;
            box-shadow: 0 1px 0 #fff inset;

    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;

    background-color: #eee;
    background-image: -webkit-gradient(linear, left bottom, left top, color-stop(0, #fff), color-stop(0.5, #eee));
    background-image: -webkit-linear-gradient(center bottom, #fff 0%, #eee 50%);
    background-image: -moz-linear-gradient(center bottom, #fff 0%, #eee 50%);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#eeeeee', endColorstr='#ffffff', GradientType=0);
    background-image: linear-gradient(top, #fff 0%, #eee 50%);
}

.select2-dropdown-open.select2-drop-above .select2-choice,
.select2-dropdown-open.select2-drop-above .select2-choices {
    border: 1px solid #5897fb;
    border-top-color: transparent;

    background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #fff), color-stop(0.5, #eee));
    background-image: -webkit-linear-gradient(center top, #fff 0%, #eee 50%);
    background-image: -moz-linear-gradient(center top, #fff 0%, #eee 50%);
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#eeeeee', endColorstr='#ffffff', GradientType=0);
    background-image: linear-gradient(bottom, #fff 0%, #eee 50%);
}

.select2-dropdown-open .select2-choice .select2-arrow {
    background: transparent;
    border-left: none;
    filter: none;
}
.select2-dropdown-open .select2-choice .select2-arrow b {
    background-position: -18px 1px;
}

/* results */
.select2-results {
    max-height: 200px;
    padding: 0 0 0 4px;
    margin: 4px 4px 4px 0;
    position: relative;
    overflow-x: hidden;
    overflow-y: auto;
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

.select2-results ul.select2-result-sub {
    margin: 0;
    padding-left: 0;
}

.select2-results ul.select2-result-sub > li .select2-result-label { padding-left: 20px }
.select2-results ul.select2-result-sub ul.select2-result-sub > li .select2-result-label { padding-left: 40px }
.select2-results ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub > li .select2-result-label { padding-left: 60px }
.select2-results ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub > li .select2-result-label { padding-left: 80px }
.select2-results ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub > li .select2-result-label { padding-left: 100px }
.select2-results ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub > li .select2-result-label { padding-left: 110px }
.select2-results ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub ul.select2-result-sub > li .select2-result-label { padding-left: 120px }

.select2-results li {
    list-style: none;
    display: list-item;
    background-image: none;
}

.select2-results li.select2-result-with-children > .select2-result-label {
    font-weight: bold;
}

.select2-results .select2-result-label {
    padding: 3px 7px 4px;
    margin: 0;
    cursor: pointer;

    min-height: 1em;

    -webkit-touch-callout: none;
      -webkit-user-select: none;
         -moz-user-select: none;
          -ms-user-select: none;
              user-select: none;
}

.select2-results .select2-highlighted {
    background: #3875d7;
    color: #fff;
}

.select2-results li em {
    background: #feffde;
    font-style: normal;
}

.select2-results .select2-highlighted em {
    background: transparent;
}

.select2-results .select2-highlighted ul {
    background: #fff;
    color: #000;
}


.select2-results .select2-no-results,
.select2-results .select2-searching,
.select2-results .select2-selection-limit {
    background: #f4f4f4;
    display: list-item;
}

/*
disabled look for disabled choices in the results dropdown
*/
.select2-results .select2-disabled.select2-highlighted {
    color: #666;
    background: #f4f4f4;
    display: list-item;
    cursor: default;
}
.select2-results .select2-disabled {
  background: #f4f4f4;
  display: list-item;
  cursor: default;
}

.select2-results .select2-selected {
    display: none;
}

.select2-more-results.select2-active {
    background: #f4f4f4 url('select2-spinner.gif') no-repeat 100%;
}

.select2-more-results {
    background: #f4f4f4;
    display: list-item;
}

/* disabled styles */

.select2-container.select2-container-disabled .select2-choice {
    background-color: #f4f4f4;
    background-image: none;
    border: 1px solid #ddd;
    cursor: default;
}

.select2-container.select2-container-disabled .select2-choice .select2-arrow {
    background-color: #f4f4f4;
    background-image: none;
    border-left: 0;
}

.select2-container.select2-container-disabled .select2-choice abbr {
    display: none;
}


/* multiselect */

.select2-container-multi .select2-choices {
    height: auto !important;
    height: 1%;
    margin: 0;
    padding: 0;
    position: relative;

    border: 1px solid #aaa;
    cursor: text;
    overflow: hidden;

    background-color: #fff;
    background-image: -webkit-gradient(linear, 0% 0%, 0% 100%, color-stop(1%, #eee), color-stop(15%, #fff));
    background-image: -webkit-linear-gradient(top, #eee 1%, #fff 15%);
    background-image: -moz-linear-gradient(top, #eee 1%, #fff 15%);
    background-image: linear-gradient(top, #eee 1%, #fff 15%);
}

.select2-locked {
  padding: 3px 5px 3px 5px !important;
}

.select2-container-multi .select2-choices {
    min-height: 26px;
}

.select2-container-multi.select2-container-active .select2-choices {
    border: 1px solid #5897fb;
    outline: none;

    -webkit-box-shadow: 0 0 5px rgba(0, 0, 0, .3);
            box-shadow: 0 0 5px rgba(0, 0, 0, .3);
}
.select2-container-multi .select2-choices li {
    float: left;
    list-style: none;
}
html[dir="rtl"] .select2-container-multi .select2-choices li
{
    float: right;
}
.select2-container-multi .select2-choices .select2-search-field {
    margin: 0;
    padding: 0;
    white-space: nowrap;
}

.select2-container-multi .select2-choices .select2-search-field input {
    padding: 5px;
    margin: 1px 0;

    font-family: sans-serif;
    font-size: 100%;
    color: #666;
    outline: 0;
    border: 0;
    -webkit-box-shadow: none;
            box-shadow: none;
    background: transparent !important;
}

.select2-container-multi .select2-choices .select2-search-field input.select2-active {
    background: #fff url('select2-spinner.gif') no-repeat 100% !important;
}

.select2-default {
    color: #999 !important;
}

.select2-container-multi .select2-choices .select2-search-choice {
    padding: 3px 5px 3px 18px;
    margin: 3px 0 3px 5px;
    position: relative;

    line-height: 13px;
    color: #333;
    cursor: default;
    border: 1px solid #aaaaaa;

    border-radius: 3px;

    -webkit-box-shadow: 0 0 2px #fff inset, 0 1px 0 rgba(0, 0, 0, 0.05);
            box-shadow: 0 0 2px #fff inset, 0 1px 0 rgba(0, 0, 0, 0.05);

    background-clip: padding-box;

    -webkit-touch-callout: none;
      -webkit-user-select: none;
         -moz-user-select: none;
          -ms-user-select: none;
              user-select: none;

    background-color: #e4e4e4;
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#eeeeee', endColorstr='#f4f4f4', GradientType=0);
    background-image: -webkit-gradient(linear, 0% 0%, 0% 100%, color-stop(20%, #f4f4f4), color-stop(50%, #f0f0f0), color-stop(52%, #e8e8e8), color-stop(100%, #eee));
    background-image: -webkit-linear-gradient(top, #f4f4f4 20%, #f0f0f0 50%, #e8e8e8 52%, #eee 100%);
    background-image: -moz-linear-gradient(top, #f4f4f4 20%, #f0f0f0 50%, #e8e8e8 52%, #eee 100%);
    background-image: linear-gradient(top, #f4f4f4 20%, #f0f0f0 50%, #e8e8e8 52%, #eee 100%);
}
html[dir="rtl"] .select2-container-multi .select2-choices .select2-search-choice
{
    margin-left: 0;
    margin-right: 5px;
}
.select2-container-multi .select2-choices .select2-search-choice .select2-chosen {
    cursor: default;
}
.select2-container-multi .select2-choices .select2-search-choice-focus {
    background: #d4d4d4;
}

.select2-search-choice-close {
    display: block;
    width: 12px;
    height: 13px;
    position: absolute;
    right: 3px;
    top: 4px;

    font-size: 1px;
    outline: none;
    background: url('select2.png') right top no-repeat;
}
html[dir="rtl"] .select2-search-choice-close {
    right: auto;
    left: 3px;
}

.select2-container-multi .select2-search-choice-close {
    left: 3px;
}

.select2-container-multi .select2-choices .select2-search-choice .select2-search-choice-close:hover {
  background-position: right -11px;
}
.select2-container-multi .select2-choices .select2-search-choice-focus .select2-search-choice-close {
    background-position: right -11px;
}

/* disabled styles */
.select2-container-multi.select2-container-disabled .select2-choices {
    background-color: #f4f4f4;
    background-image: none;
    border: 1px solid #ddd;
    cursor: default;
}

.select2-container-multi.select2-container-disabled .select2-choices .select2-search-choice {
    padding: 3px 5px 3px 5px;
    border: 1px solid #ddd;
    background-image: none;
    background-color: #f4f4f4;
}

.select2-container-multi.select2-container-disabled .select2-choices .select2-search-choice .select2-search-choice-close {    display: none;
    background: none;
}
/* end multiselect */


.select2-result-selectable .select2-match,
.select2-result-unselectable .select2-match {
    text-decoration: underline;
}

.select2-offscreen, .select2-offscreen:focus {
    clip: rect(0 0 0 0) !important;
    width: 1px !important;
    height: 1px !important;
    border: 0 !important;
    margin: 0 !important;
    padding: 0 !important;
    overflow: hidden !important;
    position: absolute !important;
    outline: 0 !important;
    left: 0px !important;
    top: 0px !important;
}

.select2-display-none {
    display: none;
}

.select2-measure-scrollbar {
    position: absolute;
    top: -10000px;
    left: -10000px;
    width: 100px;
    height: 100px;
    overflow: scroll;
}
/* Retina-ize icons */

@media only screen and (-webkit-min-device-pixel-ratio: 1.5), only screen and (min-resolution: 144dpi)  {
  .select2-search input, .select2-search-choice-close, .select2-container .select2-choice abbr, .select2-container .select2-choice .select2-arrow b {
      background-image: url('select2x2.png') !important;
      background-repeat: no-repeat !important;
      background-size: 60px 40px !important;
  }
  .select2-search input {
      background-position: 100% -21px !important;
  }
}

CODEPEN