diff --git a/forms/DropdownField.php b/forms/DropdownField.php
index c4f8a3016..08385a52f 100644
--- a/forms/DropdownField.php
+++ b/forms/DropdownField.php
@@ -96,7 +96,7 @@ class DropdownField extends SingleSelectField {
 
 		// Check disabled
 		$disabled = false;
-		if(in_array($value, $this->getDisabledItems()) && $title != $this->getEmptyString()){
+		if($this->isDisabledValue($value) && $title != $this->getEmptyString()){
 			$disabled = 'disabled';
 		}
 
diff --git a/forms/MemberDatetimeOptionsetField.php b/forms/MemberDatetimeOptionsetField.php
index 23ea8ebe9..686c5e0dc 100644
--- a/forms/MemberDatetimeOptionsetField.php
+++ b/forms/MemberDatetimeOptionsetField.php
@@ -7,6 +7,14 @@ class MemberDatetimeOptionsetField extends OptionsetField {
 
 	const CUSTOM_OPTION = '__custom__';
 
+	/**
+	 * Non-ambiguous date to use for the preview.
+	 * Must be in 'y-MM-dd HH:mm:ss' format
+	 *
+	 * @var string
+	 */
+	private static $preview_date = '25-12-2011 17:30:00';
+
 	public function Field($properties = array()) {
 		Requirements::javascript(FRAMEWORK_ADMIN_DIR . '/javascript/MemberDatetimeOptionsetField.js');
 		$options = array();
@@ -53,15 +61,27 @@ class MemberDatetimeOptionsetField extends OptionsetField {
 		$option->setField('CustomName', $this->getName().'[Custom]');
 		$option->setField('CustomValue', $this->Value());
 		if($this->Value()) {
-			$preview = Convert::raw2xml(Zend_Date::now()->toString($this->Value()));
+			$preview = Convert::raw2xml($this->previewFormat($this->Value()));
 			$option->setField('CustomPreview', $preview);
 			$option->setField('CustomPreviewLabel', _t('MemberDatetimeOptionsetField.Preview', 'Preview'));
 		}
 		return $option;
 	}
 
-	public function getItemName() {
-		return parent::getItemName() . '[Options]';
+	/**
+	 * For a given format, generate a preview for the date
+	 *
+	 * @param string $format Date format
+	 * @return string
+	 */
+	protected function previewFormat($format) {
+		$date = $this->config()->preview_date;
+		$zendDate = new Zend_Date($date, 'y-MM-dd HH:mm:ss');
+		return $zendDate->toString($format);
+	}
+
+	public function getOptionName() {
+		return parent::getOptionName() . '[Options]';
 	}
 
 	public function Type() {
diff --git a/forms/MultiSelectField.php b/forms/MultiSelectField.php
index 912f5a0b2..437fb2869 100644
--- a/forms/MultiSelectField.php
+++ b/forms/MultiSelectField.php
@@ -147,10 +147,8 @@ abstract class MultiSelectField extends SelectField {
 		if($result !== false) {
 			return $result;
 		}
-		
-		// Parse data in legacy {comma} format
-		Deprecation::notice('4.0', 'Storing multi-selection values in comma separated format is deprecated');
-		return str_replace('{comma}', ',', explode(',', $value));
+
+		throw new \InvalidArgumentException("Invalid string encoded value for multi select field");
 	}
 	
 	/**
diff --git a/forms/OptionsetField.php b/forms/OptionsetField.php
index feb1dea3d..e8d577b38 100644
--- a/forms/OptionsetField.php
+++ b/forms/OptionsetField.php
@@ -61,27 +61,50 @@ class OptionsetField extends SingleSelectField {
 	 * @return ArrayData Field option
 	 */
 	protected function getFieldOption($value, $title, $odd) {
-		// Check selection
-		$selected = $this->isSelectedValue($value, $this->Value());
-		$itemID = $this->ID() . '_' . Convert::raw2htmlid($value);
-		$extraClass = $odd ? 'odd' : 'even';
-		$extraClass .= ' val' . Convert::raw2htmlid($value);
-
 		return new ArrayData(array(
-			'ID' => $itemID,
-			'Class' => $extraClass,
-			'Name' => $this->getItemName(),
+			'ID' => $this->getOptionID($value),
+			'Class' => $this->getOptionClass($value, $odd),
+			'Name' => $this->getOptionName(),
 			'Value' => $value,
 			'Title' => $title,
-			'isChecked' => $selected,
-			'isDisabled' => $this->isDisabled() || in_array($value, $this->getDisabledItems()),
+			'isChecked' => $this->isSelectedValue($value, $this->Value()),
+			'isDisabled' => $this->isDisabledValue($value)
 		));
 		}
 
-	protected function getItemName() {
+	/**
+	 * Generate an ID property for a single option
+	 *
+	 * @param string $value
+	 * @return string
+	 */
+	protected function getOptionID($value) {
+		return $this->ID() . '_' . Convert::raw2htmlid($value);
+	}
+
+	/**
+	 * Get the "name" property for each item in the list
+	 *
+	 * @return string
+	 */
+	protected function getOptionName() {
 		return $this->getName();
 	}
 
+	/**
+	 * Get extra classes for each item in the list
+	 *
+	 * @param string $value Value of this item
+	 * @param bool $odd If this item is odd numbered in the list
+	 * @return string
+	 */
+	protected function getOptionClass($value, $odd) {
+		$oddClass = $odd ? 'odd' : 'even';
+		$valueClass = ' val' . Convert::raw2htmlid($value);
+		return $oddClass . $valueClass;
+	}
+
+
 	public function Field($properties = array()) {
 		$options = array();
 		$odd = false;
diff --git a/forms/SelectField.php b/forms/SelectField.php
index 21a7d9b89..27d30bcde 100644
--- a/forms/SelectField.php
+++ b/forms/SelectField.php
@@ -58,6 +58,19 @@ abstract class SelectField extends FormField {
 		return $this->disabledItems;
 	}
 
+	/**
+	 * Check if the given value is disabled
+	 *
+	 * @param string $value
+	 * @return bool
+	 */
+	protected function isDisabledValue($value) {
+		if($this->isDisabled()) {
+			return true;
+		}
+		return in_array($value, $this->getDisabledItems());
+	}
+
 	public function getAttributes() {
 		return array_merge(
 			parent::getAttributes(),
diff --git a/templates/forms/DropdownField.ss b/templates/forms/DropdownField.ss
index a46ce3b07..1e07c86cd 100644
--- a/templates/forms/DropdownField.ss
+++ b/templates/forms/DropdownField.ss
@@ -3,6 +3,7 @@
 	<option value="$Value.XML"
 		<% if $Selected %> selected="selected"<% end_if %>
 		<% if $Disabled %> disabled="disabled"<% end_if %>
-		><% if $Title %>$Title.XML<% else %>&nbsp;<% end_if %></option>
+		><% if $Title %>$Title.XML<% else %>&nbsp;<% end_if %>
+	</option>
 <% end_loop %>
 </select>