Question

When you unfold nested levels of your code the folded text in nested code is not indented. It begins on the beginning of the line with + instead of starting indented.

Do you know how to change it?

Answer 1

If you want the fold text to be indented at the same level as the first line of the fold, you need to prepend the indent level to the foldtext:

function! MyFoldText()
    let indent_level = indent(v:foldstart)
    let indent = repeat(' ',indent_level)
    ...
    ...   
    return indent . txt
endfunction

Here I am assuming that the string txt is your existing foldtext, so all you need to do is add it to the end of indent.

But I am not sure if that is what you want to achieve.

EDIT:

Now I have seen your picture, I’m not sure if this is what you want. You could try stripping the leading whitespace before appending to the +. So the foldtext you want will be something like indent . '+' . txt.

Maybe.