🐛 [Bug]: 画布最外层body节点高度没有占满问题

[langyjn]

Environment

chrome

Version

latest

Version

latest

Link to minimal reproduction

none

Step to reproduce

如图所示，把最外层body节点设置背景颜色没有占满整个屏幕，表面该元素没有占满屏幕，但选择节点时焦点又是整个画布，容易误导用户

What is expected

No response

What is actually happening

No response

What is your project name

tiny-engine develop

Any additional comments (optional)

No response

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Title: 🐛 [Bug]: The height of the outermost body node of the canvas is not fully occupied.