XLSX Spreadsheet - Custom Shape problem

I have somehow unintentionally inserted a custom shape into my spreadsheet. This thing is almost completely obscuring the first 26 rows of my spreadsheet. My data is still there, I just can’t see it or use it. How do I get rid this thing? Is this a bug in Libre spreadsheet?

(edit: activated screenshot)

It usually works like this: When the shape is selected, just press the DELETE button.

Please Note: “Recommendation for a clean working with LibreOffice when different office programs are used” see there last paragraph.

That’s an excellent recommendation, I do recommend as well to save always at the native format of LO and then save as... Only if compatibility is needed for other people who will receive the document (i recommend to download LO, though)

I have solved my problem. I had actually inserted four of these things, each on top of the previous one. How? I have no idea, but it happened when I was scrolling using the mouse wheel. But I found that I could select and delete them. Thanks for your help. Parenthetically, the robot preventer on this page is so annoying. I know it is necessary, but why two iterations of it?