Dragging a combo hides edges

[bartoval]

Describe the bug / 问题描述

when you enable the drag-element behavior and drag a combo, every link connected to its nodes is obscured by the layout of the combo, as if it had a lower z-index".

Reproduction link / 重现链接

No response

Steps to Reproduce the Bug or Issue / 重现步骤

1. it is possible to verify this behavior in the playground -> custom combo -> extra box by adding a background to the combo
   for example: combos: [{ id: 'combo-0', style:{fill:'red', fillOpacity:1 }}],

2. then drag the combo

G6 Version / G6 版本

🆕 5.x

Operating System / 操作系统

Linux

Browser / 浏览器

Chrome

Additional context / 补充说明

No response

[Aarebecca]

In fact, during the process of dragging an element, it is moved to the topmost layer, which is the primary cause of edges being obscured. We will consider whether to apply this action to the connected edges of the target element as well.