I have uploaded an attachment which has hyphen("-") in its name, to a confluence page.
When I try to search the attachment by clicking "insert -> images -> Search -> This space",
attachment was not found in Search result.
Confluence Search is not able to find the attachment if it has "-" in the name.

Steps to reproduce:

• Upload an attachment which has "-" in it's name to a confluence page.(Ex: Outlook-encrypt.png)
• Edit the page and try to embed the attached image on this page by clicking "images => Search => This space".
• Enter the search string as "Outlook-encrypt" and search.
• Even though attachment exists, it will not be displayed while searching with search string "Outlook-encrypt".

It's very common practise to have hyphen in file names.
There are many attachments uploaded to our Confluence pages by users have the hyphens in attachment names.
Our users are not able to search the attachments because of this issue.