A phpBB extension that keeps the Submit button greyed out and unclickable on the posting screen until the user has previewed their post. After a preview, Submit becomes available. Editing the post again locks it until a fresh preview, whether that edit is typing in the message or subject, or inserting BBCode, colours, smilies, or inline attachments from the editor controls. The Preview and Save draft buttons always stay usable.
Works on the full posting editor: new topic, reply, quote, edit, and private message compose.
Quick reply is covered too. Because the quick reply box has no inline preview, its Submit button is locked and the Full Editor & Preview button stays enabled, so the only way forward is the full editor, where the preview gate above applies.
Note: this is a UI gate in the browser. A user with browser dev tools, or with JavaScript disabled, can still submit without previewing. phpBB has no reliable way to enforce "was previewed" on the server, since a preview is a separate, stateless request. This extension nudges the normal posting flow; it is not a security control.
- Download
forcepostpreview.zipand unzip it into your board'sext/directory (it unpacks toext/ecyaz/forcepostpreview/), or copy this folder toext/ecyaz/forcepostpreview/. - Enable it via ACP → Customise → Extensions → Force Post Preview.
- After enabling (or any change), purge the cache via ACP → General → Purge the cache.
GPL 2.0 only (see license.txt).