Updated FAQ

FAQ.md

@@ -2009,6 +2009,7 @@ It is possible to configure a [regex](https://en.wikipedia.org/wiki/Regular_expr
 to match **the username** of an email address (the part before the @ sign).
 
 Note that the domain name (the parts after the @ sign) always needs to be equal to the domain name of the identity.
+This also implies that the username will be copied from a received message only if it matches the domain name of the matched identity.
 Since version 1.1640 it is possible to match the full email address with a regex, which can be useful for matching alias domain names.
 
 If you want to match a catch-all email address, this regex is usually fine, provided all usernames for the domain are yours:

index.html

@@ -1186,7 +1186,7 @@ X-Google-Original-From: Somebody &lt;somebody+extra@example.org&gt;</code></pre>
 <p>Note that identities need to be enabled to be able to be matched and that identities of other accounts will not be considered.</p>
 <p>Matching will be done only once on receiving a message, so changing the configuration will not change existing messages. You could clear local messages by long pressing a folder in the folder list and synchronize the messages again, though.</p>
 <p>It is possible to configure a <a href="https://en.wikipedia.org/wiki/Regular_expression">regex</a> in the advanced identity settings (Navigation menu &gt; Settings &gt; Manual setup and account options &gt; Identities &gt; tap the identity &gt; Advanced) to match <strong>the username</strong> of an email address (the part before the @ sign).</p>
-<p>Note that the domain name (the parts after the @ sign) always needs to be equal to the domain name of the identity. Since version 1.1640 it is possible to match the full email address with a regex, which can be useful for matching alias domain names.</p>
+<p>Note that the domain name (the parts after the @ sign) always needs to be equal to the domain name of the identity. This also implies that the username will be copied from a received message only if it matches the domain name of the matched identity. Since version 1.1640 it is possible to match the full email address with a regex, which can be useful for matching alias domain names.</p>
 <p>If you want to match a catch-all email address, this regex is usually fine, provided all usernames for the domain are yours:</p>
 <pre><code>.*</code></pre>
 <p>The username of a message being replied to will be used as the default username when editing of usernames is enabled in the advanced identity settings.</p>