Yes, use Everything mode in the quick search bar or the Attachment Content in an advanced search (the latter with "Include parent and child items of matching items" if you need to match other conditions against parent items as well).
If you click on the attachment that's not matching and look in the right-hand pane, what does it say next to Indexed?
Can you provide a Debug ID for a search that's not working, and also provide the zotero.org URL from the web library when clicking on the parent item of the attachment you're expecting to match?
The webpages I have saved in my library do not currently have parent items. I have just been saving them directly from my browser with the zotero extension.
[JavaScript Error: "C:\Program Files (x86)\Zotero\pdftotext.exe returned exit status 1" {file: "chrome://zotero/content/xpcom/utilities_internal.js" line: 756}]
Something on your system — probably security software — is preventing Zotero from running the PDF tool it uses to extract text. You can fix that or use the Zotero 7 beta, which no longer uses an external program to extract text.
The webpages I have saved in my library do not currently have parent items. I have just been saving them directly from my browser with the zotero extension.
It sounds like you're just describing regular webpage items. Only attachments — in this case webpage snapshots — have any full-text content.
From past upgrades, betas need to be absolutely rock solid and key plugins (those that will be updated) will need to be compatible. So far, Zotero 7 beta is a thing of beauty.
Yeah, I agree that the beta itself is super stable, but the lack of plugin support is surely a concern and is going to delay a prod release (and Zotero devs take this very seriously, answering a steady stream of questions by plugin devs over on the dev list)
Can you provide a Debug ID for a search that's not working, and also provide the zotero.org URL from the web library when clicking on the parent item of the attachment you're expecting to match?
https://www.zotero.org/support/adding_items_to_zotero#saving_webpages