ssb: Better handling of private message drafts.

apps/ssb/tf-compose.js

@@ -16,6 +16,7 @@ class TfComposeElement extends LitElement {
 			author: {type: String},
 			channel: {type: String},
 			new_thread: {type: Boolean},
+			recipients: {type: Array},
 		};
 	}
 
@@ -496,7 +497,17 @@ class TfComposeElement extends LitElement {
 	}
 
 	get_draft() {
-		return this.drafts[this.branch || ''] || {};
+		let key =
+			this.branch ||
+			(this.recipients ? this.recipients.join(',') : undefined) ||
+			'';
+		let draft = this.drafts[key] || {};
+		if (this.recipients && !draft.encrypt_to?.length) {
+			draft.encrypt_to = [
+				...new Set(this.recipients).union(new Set(draft.encrypt_to ?? [])),
+			];
+		}
+		return draft;
 	}
 
 	update_encrypt(event) {