How to copy formulas from a text or remove (') from ('=) in many cells WITHOUT using CSV files ?

[Yury Dubinsky <yury dubinsky gmail com>]

This question was asked on 21 May 2011 . (https://mail.gnome.org/archives/gnumeric-list/2011-May/msg00009.html)

One  advice was to use CSV files. The second advice was  to apply search-replace:

' Search for "=", replace by "=".
  On the Advanced tab, uncheck "Keep strings as strings"'

However, the second, more interactive, option doesn't work for me. 

I am getting an error message like this:

"In cell A1, the current contents 
        '=1*1 
would have been replaced by 
        =1*1 
which is invalid. 
The replace has been aborted and nothing has been changed "

Am I doing something wrong? 

Or did Gnumeric stopped supporting this behavior since 2011?