求助，按下右箭头键时光标消失

[ZongweiGao]

内容可编辑 div 中存在不可编辑的 div：

<div value="" id="step_input_0" name="step" placeholder="Tell us about step 1" class="input stepbox step_input" contenteditable="true">
<div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div><div data-class="method" class="ing-tag_0" contenteditable="false"> sdfcxz </div></div>

将光标移动到 div 的末尾。从光标的末端连续按下左箭头键可以正常的在 div 间向左移动光标，但是如果在中间的位置按下右箭头键，光标会消失，为什么会这样呢？ 怎么做才能让光标通过左右箭头键自由的左右移动。 求助！！！