Thank you!
Yacine, you're right that the shapes do not stay up-to-date in the drawing, but anyway the "search stencil" is useful.
Your drawing about the search idea is quite right, except that the "search stencil" is not meant to be temporary. The user can save it and use as long as he needs.
Nikolay, thank you for information. Now I know I should not try to get the shortcut to work, but I must change the function.
The built-in search is not worth using in this case because even if I can get it work on my own machine, it's too complicated to instruct all users.