Strange underline symbols in vim

Could you please tell me what does the underline symbols in the picture mean (they are not there in insert mode, when I write something to that place it will get underlined) and how to get ri开发者_如何学运维d of them?

thank you

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As far as I can tell, vim is underlining tab characters. This (answered) question may help you: Why is vim drawing underlines on the place of tabs and how to avoid this?