The problem is as shown in the video below. When you press the space to preview any file and click the button of "更多媒体信息", you can view more file information normally, but there is no button to return to the normal preview function.
问题如下图视频所示。当您按下空格键预览任何文件并点击按钮"更多媒体信息“，可以正常查看更多文件信息，但是没有返回正常预览功能的按钮。

In addition, it's a good idea to provide a simple background with contrasting colors.
此外，用对比色提供简单的背景也是个不错的主意。