Do NOT make a new grid

When a new grid is created, it becomes impossible to check for ALL changes when selecting a random option. Changes are made on the NEW grid, but the checking is done on only the OLD grid. This may lead to some unexpected and or strange bugs.

It would be better to keep using the same grid. Makes things just a little bit faster too. (little bit)

该 issue 未指出文件、测试或入口点。定位新 grid 的创建位置以及随机选项变更的检查位置；跟踪检查是否仍在读取旧 grid。完成标准是复用现有 grid，并针对该 grid 检查所有变更，同时不引入所报告的意外行为。

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