diff --git a/application/forms/IcingaObjectFieldForm.php b/application/forms/IcingaObjectFieldForm.php
index 91db7d4d6..f4823b5fb 100644
--- a/application/forms/IcingaObjectFieldForm.php
+++ b/application/forms/IcingaObjectFieldForm.php
@@ -2,6 +2,8 @@
 
 namespace Icinga\Module\Director\Forms;
 
+use Icinga\Module\Director\DataType\DataTypeBoolean;
+use Icinga\Module\Director\DataType\DataTypeString;
 use Icinga\Module\Director\Field\FormFieldSuggestion;
 use Icinga\Module\Director\Objects\IcingaCommand;
 use Icinga\Module\Director\Objects\IcingaHost;
@@ -17,7 +19,7 @@ class IcingaObjectFieldForm extends DirectorObjectForm
     protected $icingaObject;
 
     /** @var FormFieldSuggestion */
-    protected $formFieldSuggestion;
+    protected $fieldSuggestion;
 
     public function setIcingaObject($object)
     {
@@ -28,7 +30,6 @@ public function setIcingaObject($object)
 
     public function setup()
     {
-        $this->formFieldSuggestion = new FormFieldSuggestion();
         $object = $this->icingaObject;
         $type = $object->getShortTableName();
         $this->addHidden($type . '_id', $object->get('id'));
@@ -52,12 +53,13 @@ public function setup()
             $command = null;
         }
 
-        $descriptions = [];
-        $fields = $command ? $this->formFieldSuggestion->getCommandFields(
-            $command,
-            $this->db->enumDatafields(),
-            $descriptions
-        ) : [];
+        if ($command) {
+            $suggestions = $this->fieldSuggestion = new FormFieldSuggestion($command, $this->db->enumDatafields());
+            $fields = $suggestions->getCommandFields();
+        } else {
+            $suggestions = null;
+            $fields = [];
+        }
 
         $this->addElement('select', 'datafield_id', [
             'label'        => 'Field',
@@ -95,7 +97,7 @@ public function setup()
                     . ' user puts the focus on this field'
                 ),
                 'ignore'      => true,
-                'value'       => array_key_exists($id, $descriptions) ? $descriptions[$id] : null,
+                'value'       => $suggestions ? $suggestions->getDescription($id) : null,
                 'rows'        => '3',
             ]);
         }
@@ -153,7 +155,9 @@ public function onSuccess()
                 'varname'     => trim($fieldId, '$'),
                 'caption'     => $this->getValue('caption'),
                 'description' => $this->getValue('description'),
-                'datatype'    => 'Icinga\Module\Director\DataType\DataTypeString',
+                'datatype'    => $this->fieldSuggestion && $this->fieldSuggestion->isBoolean($fieldId)
+                    ? DataTypeBoolean::class
+                    : DataTypeString::class
             ]);
             $field->store($this->getDb());
             $this->setElementValue('datafield_id', $field->get('id'));
diff --git a/doc/82-Changelog.md b/doc/82-Changelog.md
index 8f71bfd78..e50cd29bc 100644
--- a/doc/82-Changelog.md
+++ b/doc/82-Changelog.md
@@ -17,6 +17,7 @@ This version hasn't been released yet
 * FEATURE: Sort Template trees by name (#2691)
 * FEATURE: Branch and Sync diff/preview now shows related host for services (#2736)
 * FEATURE: Show more details for assign filter parsing errors (#2667)
+* FEATURE: Fields from set_if are now being proposed (#514)
 * FIX: do not fail for (some) Service Dependencies (#2669, #1142)
 * FIX: Service Sets can now be searched by Service name in branches too (#2738)
 * FIX: Template usage table had no header (#2780)
@@ -45,7 +46,6 @@ This version hasn't been released yet
 * FIX: complaint about overdue jobs was not correct (#2680, #2681)
 
 ### Internals
-
 * FIX: group membership is no longer resolved when not needed (#2048)
 
 ### Fixed issues
diff --git a/library/Director/Field/FormFieldSuggestion.php b/library/Director/Field/FormFieldSuggestion.php
index 72db096d2..4fa5f33dd 100644
--- a/library/Director/Field/FormFieldSuggestion.php
+++ b/library/Director/Field/FormFieldSuggestion.php
@@ -9,84 +9,149 @@ class FormFieldSuggestion
 {
     use TranslationHelper;
 
-    public function getCommandFields(
+    /**
+     * Macro/Argument names used in command argument values
+     *
+     * @var array
+     */
+    protected $argumentVars = [];
+    protected $suggestedFields = [];
+    protected $blacklistedVars = [];
+    protected $descriptions = [];
+    protected $booleans = [];
+
+    /** @var IcingaCommand */
+    protected $command;
+
+    /** @var array */
+    protected $existingFields;
+
+    protected $fields = null;
+
+    public function __construct(
         IcingaCommand $command,
-        array $existingFields,
-        array &$descriptions
-    ): array
+        array $existingFields
+    ) {
+        $this->command = $command;
+        $this->existingFields = $existingFields;
+    }
+
+    public function getCommandFields(): array
+    {
+        if ($this->fields === null) {
+            $this->fields = $this->prepareFields();
+        }
+
+        return $this->fields;
+    }
+
+    protected function prepareFields(): array
     {
         // TODO: remove assigned ones!
-        $argumentVars = [];
-        $blacklistedVars = [];
-        $suggestedFields = [];
-        $booleans = [];
 
-        foreach ($existingFields as $id => $field) {
+        foreach ($this->existingFields as $id => $field) {
             if (preg_match('/ \(([^)]+)\)$/', $field, $m)) {
-                $blacklistedVars['$' . $m[1] . '$'] = $id;
+                $this->blacklistedVars['$' . $m[1] . '$'] = $id;
             }
         }
-        foreach ($command->arguments() as $arg) {
+        foreach ($this->command->arguments() as $arg) {
             if ($arg->argument_format === 'string') {
                 foreach (self::extractMacroNamesFromString($arg->argument_value) as $val) {
-                    self::addSuggestion(
-                        $val,
-                        $arg->description,
-                        $blacklistedVars,
-                        $existingFields,
-                        $suggestedFields,
-                        $argumentVars,
-                        $descriptions
-                    );
+                    $this->addSuggestion($val, $arg->description, $this->argumentVars);
                 }
             }
+
+            if (($arg->set_if_format === 'string' || $arg->set_if_format === null)
+                && $val = self::getMacroIfStringIsSingleMacro($arg->set_if)
+            ) {
+                $this->addSuggestion($val, $arg->description, $this->booleans);
+            }
         }
+        asort($this->suggestedFields, SORT_NATURAL | SORT_FLAG_CASE);
+        ksort($this->argumentVars);
+        ksort($this->booleans);
+        asort($this->existingFields, SORT_NATURAL | SORT_FLAG_CASE);
 
         // Prepare combined fields array
         $fields = [];
-        if (! empty($suggestedFields)) {
-            asort($suggestedFields, SORT_NATURAL | SORT_FLAG_CASE);
-            $fields[$this->translate('Suggested fields')] = $suggestedFields;
+        if (! empty($this->suggestedFields)) {
+            $fields[$this->translate('Suggested fields')] = $this->suggestedFields;
+        }
+
+        if (! empty($this->argumentVars)) {
+            $fields[$this->translate('Argument macros')] = $this->argumentVars;
         }
 
-        if (! empty($argumentVars)) {
-            ksort($argumentVars);
-            $fields[$this->translate('Argument macros')] = $argumentVars;
+        if (! empty($this->booleans)) {
+            $fields[$this->translate('Flags (boolean) arguments')] = $this->booleans;
         }
 
-        if (! empty($existingFields)) {
-            asort($existingFields, SORT_NATURAL | SORT_FLAG_CASE);
-            $fields[$this->translate('Other available fields')] = $existingFields;
+        if (! empty($this->existingFields)) {
+            $fields[$this->translate('Other available fields')] = $this->existingFields;
         }
 
         return $fields;
     }
 
-    protected static function addSuggestion(
+    public function getDescription($id)
+    {
+        if (array_key_exists($id, $this->descriptions)) {
+            return $this->descriptions[$id];
+        }
+
+        return null;
+    }
+
+    public function isBoolean(string $macro): bool
+    {
+        return isset($this->booleans[$macro]);
+    }
+
+    protected function addSuggestion(
         string $val,
         ?string $description,
-        array $blacklistedVars,
-        array &$existingFields,
-        array &$suggestedFields,
-        array &$targetList,
-        array &$descriptions
+        array &$targetList
     ) {
-        if (array_key_exists($val, $blacklistedVars)) {
-            $id = $blacklistedVars[$val];
+        if (array_key_exists($val, $this->blacklistedVars)) {
+            $id = $this->blacklistedVars[$val];
 
             // Hint: if not set it might already have been
             //       removed in this loop
-            if (array_key_exists($id, $existingFields)) {
-                $suggestedFields[$id] = $existingFields[$id];
-                unset($existingFields[$id]);
+            if (array_key_exists($id, $this->existingFields)) {
+                $this->suggestedFields[$id] = $this->existingFields[$id];
+                unset($this->existingFields[$id]);
             }
         } else {
             $targetList[$val] = $val;
-            $descriptions[$val] = $description;
+            $this->descriptions[$val] = $description;
+        }
+    }
+
+    /**
+     * Returns a macro name string ($macro_name$), if the given string is such, null otherwise
+     *
+     * @param ?string $string
+     * @return ?string
+     */
+    protected static function getMacroIfStringIsSingleMacro(?string $string): ?string
+    {
+        if ($string === null) {
+            return null;
+        }
+
+        if (preg_match('/^(\$[a-z0-9_]+\$)$/i', $string, $matches)) {
+            return $matches[1];
         }
 
+        return null;
     }
 
+    /**
+     * Extracts all macro names ($macro_name$) from a given string
+     *
+     * @param ?string $string
+     * @return array
+     */
     protected static function extractMacroNamesFromString(?string $string): array
     {
         if ($string !== null && preg_match_all('/(\$[a-z0-9_]+\$)/i', $string, $matches, PREG_PATTERN_ORDER)) {