This is the first time I'm hearing of this problem.
I can search and replace text without any trouble.
Did you delete the application preferences? Always do that after a crash, or when the application misbehaves. Maybe that is enough.
To delete preferences, hold down command and option while starting the application and click Delete Custom Settings. The application will start with default settings and open an "Untitled" library. Adjust the settings, reopen the library you were working, and see how it works now.
If the issue persists, there could be a bad font - corrupted fonts can cause crashes. I'd validate the fonts in Font Book and delete and ones that don't pass the validation.
If the issue persists still: Please run Etrecheck and post its full report here.
Use the "additional text" button and paste the report into the text box.