Hi,

when running M-x grep-find the cursor is in minibuffer at EOL. In
order to insert the expression, cursor is needed before braces  - see png.

The patch attached shows an example how to provide this. There might
be more cases to consider.

Thanks,
Andreas

GNU Emacs 27.0.50 (build 1, i686-pc-linux-gnu, X toolkit, Xaw3d scroll 
bars) of 2019-06-04