Add `box-sizing` to another area

This closes https://github.com/select2/select2/issues/3029.

dist/css/select2.css

@@ -160,6 +160,7 @@
   border-radius: 4px;
   cursor: text; }
   .select2-container--default .select2-selection--multiple .select2-selection__rendered {
+    box-sizing: border-box;
     list-style: none;
     margin: 0;
     padding: 0 5px;

dist/js/select2.amd.full.js

@@ -4323,6 +4323,8 @@ define('select2/core',[
         attributes: true,
         subtree: false
       });
+    } else if (this.$element[0].addEventListener) {
+      this.$element[0].addEventListener('DOMAttrModified', self._sync, false);
     }
   };
 
@@ -4585,6 +4587,9 @@ define('select2/core',[
     if (this._observer != null) {
       this._observer.disconnect();
       this._observer = null;
+    } else if (this.$element[0].removeEventListener) {
+      this.$element[0]
+        .removeEventListener('DOMAttrModified', this._sync, false);
     }
 
     this._sync = null;

dist/js/select2.amd.js

@@ -4323,6 +4323,8 @@ define('select2/core',[
         attributes: true,
         subtree: false
       });
+    } else if (this.$element[0].addEventListener) {
+      this.$element[0].addEventListener('DOMAttrModified', self._sync, false);
     }
   };
 
@@ -4585,6 +4587,9 @@ define('select2/core',[
     if (this._observer != null) {
       this._observer.disconnect();
       this._observer = null;
+    } else if (this.$element[0].removeEventListener) {
+      this.$element[0]
+        .removeEventListener('DOMAttrModified', this._sync, false);
     }
 
     this._sync = null;

dist/js/select2.full.js

@@ -4762,6 +4762,8 @@ define('select2/core',[
         attributes: true,
         subtree: false
       });
+    } else if (this.$element[0].addEventListener) {
+      this.$element[0].addEventListener('DOMAttrModified', self._sync, false);
     }
   };
 
@@ -5024,6 +5026,9 @@ define('select2/core',[
     if (this._observer != null) {
       this._observer.disconnect();
       this._observer = null;
+    } else if (this.$element[0].removeEventListener) {
+      this.$element[0]
+        .removeEventListener('DOMAttrModified', this._sync, false);
     }
 
     this._sync = null;

dist/js/select2.js

@@ -4762,6 +4762,8 @@ define('select2/core',[
         attributes: true,
         subtree: false
       });
+    } else if (this.$element[0].addEventListener) {
+      this.$element[0].addEventListener('DOMAttrModified', self._sync, false);
     }
   };
 
@@ -5024,6 +5026,9 @@ define('select2/core',[
     if (this._observer != null) {
       this._observer.disconnect();
       this._observer = null;
+    } else if (this.$element[0].removeEventListener) {
+      this.$element[0]
+        .removeEventListener('DOMAttrModified', this._sync, false);
     }
 
     this._sync = null;

src/scss/theme/default/_multiple.scss

@@ -5,6 +5,7 @@
   cursor: text;
 
   .select2-selection__rendered {
+    box-sizing: border-box;
     list-style: none;
     margin: 0;
     padding: 0 5px;