Contents on Zathura are not recoganizable when doing forward search if the cursor stays on an equation environment about vimtex

[lervag]

If my cursor stays on an equation on gVim, the corresponding contents on Zathura are not recognizable when I do a forward search (\lv), as shown in the following screenshot.

This is not really a VimTeX issue, but instead an issue about Zathura and its forward search feature. I don't really know the answer here, but I think you may want to look into man zathurarc. E.g. options like highlight-active-color.

My vimrc settings: …

You don't need g:tex_flavor and you are setting things that you don't need. Here's an equivalent configuration:

let g:vimtex_compiler_latexmk = {
      \ 'out_dir': 'output',
      \ 'aux_dir': 'aux',
      \ 'options' : [
      \   '-verbose',
      \   '-file-line-error',
      \   '-synctex=1',
      \   '-interaction=nonstopmode',
      \   '-shell-escape',
      \ ],
      \}
let g:vimtex_view_method = 'zathura'