Horizontal split interferes with file tree

[ByteDrummer]

The horizontal split seems to go into the file tree by changing the vertical split's colors. How would I go about fixing this? See the screenshot below:

[xeluxee]

That could be related to NvimTreeVertSplit highlight group What terminal are you using?

[ByteDrummer]

I'm using Alacritty. That highlight group doesn't seem to affect it. I set hi NvimTreeVertSplit guifg=#FFFFFF guibg=NONE and this is the result:

[xeluxee]

NvimTree vertical split line was hidden to make NvimTree look clearer. But when laststatus is 3 an extra box-drawing character appears on the left, so it looks weird. Launch :hi clear NvimTreeVertSplit to make it look normal I don't know it there's a highlight group for that character, but as a workaround you can customize NvimTreeVertSplit: see https://github.com/navarasu/onedark.nvim#customization

require('onedark').setup {
  highlights = {
    NvimTreeVertSplit = { fg = '$bg3', bg = '$bg0' },
  }
}

[ByteDrummer]

Thanks for the suggestion. That helped me understand what's going on.

That extra character, along with the rest of the horizontal split, seems to belong to the same group as WinSeparator: https://neovim.io/doc/user/options.html#'fillchars'. For some reason, the character switches between ├ to │ when changing buffer focus without NvimTreeVertSplit being redrawn, so it gets rendered above.

This looks like it's a bug with Neovim, and it's already been reported: https://github.com/neovim/neovim/issues/17765#issuecomment-1115739104