speedbar sr-speedar flush cache and full expand current buffer when save it

I’m using sr-speedbar.

I would like it to automatically full expand current file buffer, and update the bar content when I save the current buffer.

I tried something like : (add-hook 'after-save-hook 'speedbar-flush-expand-line) in my init file but it does not work since my cursor is in my file buffer window.
The point is to have tags of file buffer always displayed and up to date with file content on disk.