I just double checked and it worked for me without issue for both engines you have on that page.
This is what I did:
1. Typed in “operation” on your main page search, clicked the magnifier. It took me to the advanced search results page. So far so good.
2. Then I deselected content and excerpt on the left search and typed in “operation” again: https://i.imgur.com/L8ai5IR.png
3. I got 3 results: https://i.imgur.com/Q0raY7m.png
Am I missing something?
I don't think I understand the issue with the $ symbol. Could you please perhaps make a screenshot of the problem? I don't know where to look for it or where it should appear, I think I just don't understand, I'm sorry.Best,
If you like my products, don't forget to rate them on codecanyon :)