fix: unselect grid selection before init (fix: #1300)

[black7375]

Please check if the PR fulfills these requirements

• [x] It's the right issue type on the title
• [x] When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
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Description

Clear a grid selection that was created before the coordinates of the grid selection were initialized.

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