diff --git a/ident_switch-form.js b/ident_switch-form.js
index b5e44dc..870ef50 100644
--- a/ident_switch-form.js
+++ b/ident_switch-form.js
@@ -43,9 +43,14 @@ $(function() {
 		});
 	});
 
-	// Delimiter blur handler
-	$("INPUT[name='_ident_switch.form.imap.delimiter']").on('blur', function() {
-		plugin_switchIdent_clearIfDefault($(this));
+	// Delimiter mode handler
+	$("SELECT[name='_ident_switch.form.imap.delimiter_mode']").on('change', function() {
+		if ($(this).val() === 'manual') {
+			$('#ident-switch-delimiter-input').show();
+		} else {
+			$('#ident-switch-delimiter-input').hide();
+			$("INPUT[name='_ident_switch.form.imap.delimiter']").val('');
+		}
 	});
 });
 
@@ -113,6 +118,9 @@ function plugin_switchIdent_processPreconfig() {
 		$("SELECT[name='_ident_switch.form.smtp.security']").prop("disabled", true);
 		$("INPUT[name='_ident_switch.form.smtp.port']").prop("disabled", true);
 
+		$("SELECT[name='_ident_switch.form.imap.delimiter_mode']").prop("disabled", true);
+		$("INPUT[name='_ident_switch.form.imap.delimiter']").prop("disabled", true);
+
 		$("INPUT[name='_ident_switch.form.sieve.host']").prop("disabled", true);
 		$("SELECT[name='_ident_switch.form.sieve.security']").prop("disabled", true);
 		$("INPUT[name='_ident_switch.form.sieve.port']").prop("disabled", true);
diff --git a/lib/IdentSwitchForm.php b/lib/IdentSwitchForm.php
index 4e1d45b..72cf30e 100644
--- a/lib/IdentSwitchForm.php
+++ b/lib/IdentSwitchForm.php
@@ -54,7 +54,7 @@ class IdentSwitchForm
 			$prefix . 'port' => ['type' => 'text', 'size' => 5, 'placeholder' => 993],
 			$prefix . 'username' => ['type' => 'text', 'size' => 64, 'placeholder' => $record['email'] ?? ''],
 			$prefix . 'password' => ['type' => 'password', 'size' => 64],
-			$prefix . 'delimiter' => ['type' => 'text', 'size' => 1, 'placeholder' => 'Auto'],
+			$prefix . 'delimiter' => ['value' => $this->build_delimiter_field($prefix, $record)],
 		];
 	}
 
@@ -169,6 +169,31 @@ class IdentSwitchForm
 		return $select->show($current) . $warning;
 	}
 
+	/**
+	 * Build the delimiter field with Auto/Manual mode select.
+	 *
+	 * @param string $prefix  Form field prefix (e.g. 'ident_switch.form.imap.').
+	 * @param array  $record  Identity record data.
+	 * @return string Rendered HTML select + text input.
+	 */
+	private function build_delimiter_field(string $prefix, array &$record): string
+	{
+		$delimValue = $record[$prefix . 'delimiter'] ?? '';
+		$mode = ($delimValue !== '' && $delimValue !== null) ? 'manual' : 'auto';
+
+		$select = new html_select(['name' => "_{$prefix}delimiter_mode"]);
+		$select->add($this->plugin->gettext('form.imap.delimiter.auto'), 'auto');
+		$select->add($this->plugin->gettext('form.imap.delimiter.manual'), 'manual');
+
+		$hidden = $mode === 'auto' ? ' style="display:none"' : '';
+		$input = new html_inputfield(['name' => "_{$prefix}delimiter", 'size' => 1]);
+
+		return $select->show($mode)
+			. ' <span id="ident-switch-delimiter-input"' . $hidden . '>'
+			. $input->show($delimValue)
+			. '</span>';
+	}
+
 	/**
 	 * Parse scheme prefix from a host string.
 	 *
@@ -531,10 +556,15 @@ class IdentSwitchForm
 			return $retVal;
 		}
 
-		$retVal['imap.delimiter'] = self::get_field_value('imap', 'delimiter');
-		if (strlen($retVal['imap.delimiter'] ?? '') > 1) {
-			$retVal['err'] = 'delim.long';
-			return $retVal;
+		$delimMode = self::get_field_value('imap', 'delimiter_mode');
+		if ($delimMode === 'manual') {
+			$retVal['imap.delimiter'] = self::get_field_value('imap', 'delimiter');
+			if (strlen($retVal['imap.delimiter'] ?? '') > 1) {
+				$retVal['err'] = 'delim.long';
+				return $retVal;
+			}
+		} else {
+			$retVal['imap.delimiter'] = null;
 		}
 
 		$retVal['imap.user'] = self::get_field_value('imap', 'username');
diff --git a/localization/de_DE.inc b/localization/de_DE.inc
index 517d11e..8cf2b45 100644
--- a/localization/de_DE.inc
+++ b/localization/de_DE.inc
@@ -37,6 +37,8 @@ $labels['form.imap.password'] = 'Passwort';
 
 // Folder hierarchy delimiter
 $labels['form.imap.delimiter'] = 'Ordnerhierarchie-Trennzeichen';
+$labels['form.imap.delimiter.auto'] = 'Automatisch erkennen';
+$labels['form.imap.delimiter.manual'] = 'Manuell';
 
 // Value in \'Username\' field is too long (64 chars max).
 $labels['err.user.long'] = 'Der Wert in Feld \'Benutzername\' ist zu lang (max. 64 Zeichen).';
diff --git a/localization/en_US.inc b/localization/en_US.inc
index 14bfcaf..4fbd724 100644
--- a/localization/en_US.inc
+++ b/localization/en_US.inc
@@ -31,6 +31,8 @@ $labels['form.imap.port'] = 'Port';
 
 // Folder hierarchy delimiter
 $labels['form.imap.delimiter'] = 'Folder hierarchy delimiter';
+$labels['form.imap.delimiter.auto'] = 'Auto-detect';
+$labels['form.imap.delimiter.manual'] = 'Manual';
 
 // Username
 $labels['form.imap.username'] = 'Username';
diff --git a/localization/fr_FR.inc b/localization/fr_FR.inc
index 57ffc6b..4c704cc 100644
--- a/localization/fr_FR.inc
+++ b/localization/fr_FR.inc
@@ -37,6 +37,8 @@ $labels['form.imap.password'] = 'Mot de passe';
 
 // Folder hierarchy delimiter
 $labels['form.imap.delimiter'] = 'Délimiteur de hiérarchie des dossiers';
+$labels['form.imap.delimiter.auto'] = 'Auto-détection';
+$labels['form.imap.delimiter.manual'] = 'Manuel';
 
 // Value in \'Username\' field of IMAP section is too long (64 chars max).
 $labels['err.user.long'] = 'La valeur du champ \'Nom d\'utilisateur\' de la section IMAP est trop longue (64 caractères max).';
diff --git a/localization/it_IT.inc b/localization/it_IT.inc
index 856b384..1d374bc 100644
--- a/localization/it_IT.inc
+++ b/localization/it_IT.inc
@@ -31,6 +31,8 @@ $labels['form.imap.port'] = 'Porta';
 
 // Folder hierarchy delimiter
 $labels['form.imap.delimiter'] = 'Delimitatore gerarchico delle cartelle';
+$labels['form.imap.delimiter.auto'] = 'Rilevamento automatico';
+$labels['form.imap.delimiter.manual'] = 'Manuale';
 
 // Username
 $labels['form.imap.username'] = 'Username';
diff --git a/localization/nl_NL.inc b/localization/nl_NL.inc
index 9eacbae..953cb0b 100644
--- a/localization/nl_NL.inc
+++ b/localization/nl_NL.inc
@@ -31,6 +31,8 @@ $labels['form.imap.port'] = 'Poortnummer';
 
 // Folder hierarchy delimiter
 $labels['form.imap.delimiter'] = 'Map hiërarchie scheidingsteken';
+$labels['form.imap.delimiter.auto'] = 'Automatisch detecteren';
+$labels['form.imap.delimiter.manual'] = 'Handmatig';
 
 // Username
 $labels['form.imap.username'] = 'Gebruikersnaam';
diff --git a/localization/ru_RU.inc b/localization/ru_RU.inc
index 8406f5f..92c374f 100644
--- a/localization/ru_RU.inc
+++ b/localization/ru_RU.inc
@@ -31,6 +31,8 @@ $labels['form.imap.port'] = 'Порт';
 
 // Folder hierarchy delimiter
 $labels['form.imap.delimiter'] = 'Разделитель в иерархии папок';
+$labels['form.imap.delimiter.auto'] = 'Автоопределение';
+$labels['form.imap.delimiter.manual'] = 'Вручную';
 
 // Username
 $labels['form.imap.username'] = 'Имя пользователя';
diff --git a/localization/sl_SI.inc b/localization/sl_SI.inc
index 1f6d5d3..9ef9800 100644
--- a/localization/sl_SI.inc
+++ b/localization/sl_SI.inc
@@ -31,6 +31,8 @@ $labels['form.imap.port'] = 'Vrata';
 
 // Folder hierarchy delimiter
 $labels['form.imap.delimiter'] = 'Ločilo hierarhije map';
+$labels['form.imap.delimiter.auto'] = 'Samodejno zaznavanje';
+$labels['form.imap.delimiter.manual'] = 'Ročno';
 
 // Username
 $labels['form.imap.username'] = 'Uporabniško ime';