AndyScherzinger · Nov 4, 2026 · Nov 4, 2026
diff --git a/docs/DataStructure.md b/docs/DataStructure.md
@@ -307,6 +307,7 @@ Supported trigger types for conditional questions:
 | ----------------- | --------------------------------------------------------------------------- | ------------------------------------------------- |
 | `multiple_unique` | `option_selected`                                                           | Radio buttons - the selected option               |
 | `dropdown`        | `option_selected`                                                           | Dropdown - the selected option                    |
+| `multiple`        | `options_combination`                                                       | Checkboxes - all options of a combination         |
 
 A branch is shown when any of its conditions matches. Several branches can be shown at once.
 
@@ -348,6 +349,14 @@ Conditions determine when a branch is activated. The structure depends on the tr
 { "type": "option_selected", "optionId": 42 }
 ```
 
+#### options_combination (for multiple)
+
+```json
+{ "type": "options_combination", "optionIds": [42, 43] }
+```
+
+All options in `optionIds` must be selected for the condition to match.
+
 ### Conditional Question Example
 
 A complete conditional question structure:

diff --git a/lib/Constants.php b/lib/Constants.php
@@ -260,6 +260,7 @@ class Constants {
 	 * Condition types for conditional questions
 	 */
 	public const CONDITION_TYPE_OPTION_SELECTED = 'option_selected';
+	public const CONDITION_TYPE_OPTIONS_COMBINATION = 'options_combination';
 
 	/**
 	 * Trigger types allowed for conditional questions
@@ -268,6 +269,7 @@ class Constants {
 	public const CONDITIONAL_TRIGGER_TYPES = [
 		self::ANSWER_TYPE_MULTIPLEUNIQUE => [self::CONDITION_TYPE_OPTION_SELECTED],
 		self::ANSWER_TYPE_DROPDOWN => [self::CONDITION_TYPE_OPTION_SELECTED],
+		self::ANSWER_TYPE_MULTIPLE => [self::CONDITION_TYPE_OPTIONS_COMBINATION],
 	];
 
 	/**

diff --git a/lib/Service/FormsService.php b/lib/Service/FormsService.php
@@ -156,6 +156,9 @@ public static function mapConditionOptionIds(array $extraSettings, array $option
 				if (isset($condition['optionId'])) {
 					$extraSettings['branches'][$branchIndex]['conditions'][$conditionIndex]['optionId'] = $optionIdMap[$condition['optionId']] ?? $condition['optionId'];
 				}
+				if (isset($condition['optionIds']) && is_array($condition['optionIds'])) {
+					$extraSettings['branches'][$branchIndex]['conditions'][$conditionIndex]['optionIds'] = array_map(static fn ($optionId) => $optionIdMap[$optionId] ?? $optionId, $condition['optionIds']);
+				}
 			}
 		}
 		return $extraSettings;
@@ -953,6 +956,10 @@ private function areBranchConditionsValid(string $triggerType, array $conditions
 			if (isset($condition['optionId']) && !is_int($condition['optionId'])) {
 				return false;
 			}
+			if (isset($condition['optionIds'])
+				&& (!is_array($condition['optionIds']) || array_filter($condition['optionIds'], static fn ($id) => !is_int($id)) !== [])) {
+				return false;
+			}
 			foreach (['value', 'min', 'max'] as $key) {
 				if (isset($condition[$key]) && !is_scalar($condition[$key])) {
 					return false;

diff --git a/lib/Service/SubmissionService.php b/lib/Service/SubmissionService.php
@@ -1147,6 +1147,18 @@ private function evaluateBranchConditions(string $triggerType, array $triggerAns
 					}
 				}
 				return false;
+			case Constants::ANSWER_TYPE_MULTIPLE:
+				// Multi-select: the branch is active if all option ids of any of its conditions are selected
+				foreach ($conditions as $condition) {
+					$optionIds = $condition['optionIds'] ?? [];
+					if (empty($optionIds) || !is_array($optionIds)) {
+						continue;
+					}
+					if (array_diff(array_map('strval', $optionIds), $selectedOptionIds) === []) {
+						return true;
+					}
+				}
+				return false;
 			default:
 				return false;
 		}

diff --git a/src/components/Questions/BranchConditionEditor.vue b/src/components/Questions/BranchConditionEditor.vue
@@ -5,17 +5,30 @@
 
 <template>
 	<div class="branch-condition-editor">
-		<!-- Option-based conditions (radio, dropdown) -->
+		<!-- Option-based conditions (radio, dropdown, checkbox) -->
 		<template v-if="isOptionBasedTrigger">
 			<div class="condition-options">
+				<!-- Single select for radio/dropdown -->
 				<NcSelect
+					v-if="isSingleSelect"
 					:inputLabel="conditionLabel"
 					:modelValue="selectedOptions"
 					:options="optionsList"
 					:placeholder="t('forms', 'Select an option')"
 					:multiple="false"
 					label="text"
 					@update:modelValue="onSingleOptionSelect" />
+
+				<!-- Multi select for checkboxes -->
+				<NcSelect
+					v-else
+					:inputLabel="conditionLabel"
+					:modelValue="selectedOptions"
+					:options="optionsList"
+					:placeholder="t('forms', 'Select options combination')"
+					:multiple="true"
+					label="text"
+					@update:modelValue="onMultipleOptionsSelect" />
 			</div>
 		</template>
 	</div>
@@ -62,17 +75,29 @@ export default {
 
 	computed: {
 		/**
-		 * Check if trigger is option-based (radio, dropdown)
+		 * Check if trigger is option-based (radio, dropdown, checkbox)
 		 */
 		isOptionBasedTrigger() {
+			return ['multiple_unique', 'dropdown', 'multiple'].includes(
+				this.triggerType,
+			)
+		},
+
+		/**
+		 * Check if trigger is single-select (radio, dropdown)
+		 */
+		isSingleSelect() {
 			return ['multiple_unique', 'dropdown'].includes(this.triggerType)
 		},
 
 		/**
 		 * Label for option-based conditions
 		 */
 		conditionLabel() {
-			return t('forms', 'Show when selected:')
+			if (this.isSingleSelect) {
+				return t('forms', 'Show when selected:')
+			}
+			return t('forms', 'Show when all selected:')
 		},
 
 		/**
@@ -90,15 +115,22 @@ export default {
 		 */
 		selectedOptions() {
 			if (!this.branch.conditions || this.branch.conditions.length === 0) {
-				return null
+				return this.isSingleSelect ? null : []
 			}
 
-			const selectedIds = this.branch.conditions.map((c) => c.optionId)
+			let selectedIds
+			if (this.isSingleSelect) {
+				// Single select uses optionId in each condition
+				selectedIds = this.branch.conditions.map((c) => c.optionId)
+			} else {
+				// Multi select uses optionIds array in first condition
+				selectedIds = this.branch.conditions[0]?.optionIds || []
+			}
 			const selected = this.optionsList.filter((opt) =>
 				selectedIds.includes(opt.id),
 			)
 
-			return selected[0] || null
+			return this.isSingleSelect ? selected[0] || null : selected
 		},
 	},
 
@@ -113,6 +145,17 @@ export default {
 			this.emitUpdate({ conditions })
 		},
 
+		/**
+		 * Handle multiple option selection (checkbox)
+		 *
+		 * @param {Array} options The selected options array
+		 */
+		onMultipleOptionsSelect(options) {
+			const optionIds = options.map((opt) => opt.id)
+			const conditions = optionIds.length > 0 ? [{ optionIds }] : []
+			this.emitUpdate({ conditions })
+		},
+
 		/**
 		 * Emit branch update
 		 *

diff --git a/src/components/Questions/QuestionConditional.vue b/src/components/Questions/QuestionConditional.vue
@@ -409,7 +409,7 @@ export default defineComponent({
 			const groups = [
 				{
 					label: t('forms', 'Choice'),
-					types: ['multiple_unique', 'dropdown'],
+					types: ['multiple_unique', 'multiple', 'dropdown'],
 				},
 			]
 
@@ -445,10 +445,12 @@ export default defineComponent({
 		},
 
 		/**
-		 * Check if trigger type uses predefined options (radio, dropdown)
+		 * Check if trigger type uses predefined options (radio, dropdown, checkbox)
 		 */
 		isOptionBasedTrigger() {
-			return ['multiple_unique', 'dropdown'].includes(this.triggerType)
+			return ['multiple_unique', 'dropdown', 'multiple'].includes(
+				this.triggerType,
+			)
 		},
 
 		triggerComponent() {
@@ -694,8 +696,15 @@ export default defineComponent({
 				})
 			}
 
-			if (this.isOptionBasedTrigger) {
-				const optionIds = branch.conditions.map((c) => c.optionId)
+			if (
+				['multiple_unique', 'dropdown', 'multiple'].includes(
+					this.triggerType,
+				)
+			) {
+				// Checkbox conditions hold a combination of options
+				const optionIds = branch.conditions.flatMap(
+					(c) => c.optionIds ?? [c.optionId],
+				)
 				const optionTexts = optionIds
 					.map((id) => this.options.find((o) => o.id === id)?.text)
 					.filter(Boolean)
@@ -935,6 +944,23 @@ export default defineComponent({
 				)
 			}
 
+			if (this.triggerType === 'multiple') {
+				// Multi-select: all condition option IDs must be selected
+				for (const c of branch.conditions) {
+					const optionIds = c.optionIds
+					if (!Array.isArray(optionIds) || optionIds.length === 0) {
+						continue
+					}
+					const allSelected = optionIds.every((id) =>
+						triggerValuesAsStrings.includes(String(id)),
+					)
+					if (allSelected) {
+						return true
+					}
+				}
+				return false
+			}
+
 			return false
 		},
 

diff --git a/tests/Unit/Service/FormsServiceTest.php b/tests/Unit/Service/FormsServiceTest.php
@@ -1926,6 +1926,16 @@ public static function dataAreExtraSettingsValid() {
 				'questionType' => Constants::ANSWER_TYPE_CONDITIONAL,
 				'expected' => true
 			],
+			'valid-conditional-multiple-trigger' => [
+				'extraSettings' => [
+					'triggerType' => Constants::ANSWER_TYPE_MULTIPLE,
+					'branches' => [
+						['id' => 'branch-1', 'conditions' => [['type' => 'options_combination', 'optionIds' => [1, 2]]]]
+					]
+				],
+				'questionType' => Constants::ANSWER_TYPE_CONDITIONAL,
+				'expected' => true
+			],
 			'invalid-conditional-missing-triggerType' => [
 				'extraSettings' => [
 					'branches' => [
@@ -2031,6 +2041,16 @@ public static function dataAreExtraSettingsValid() {
 				'questionType' => Constants::ANSWER_TYPE_CONDITIONAL,
 				'expected' => false
 			],
+			'invalid-conditional-option-ids-not-numbers' => [
+				'extraSettings' => [
+					'triggerType' => Constants::ANSWER_TYPE_MULTIPLE,
+					'branches' => [
+						['id' => 'branch-1', 'conditions' => [['type' => 'options_combination', 'optionIds' => [1, 'two']]]]
+					]
+				],
+				'questionType' => Constants::ANSWER_TYPE_CONDITIONAL,
+				'expected' => false
+			],
 			'invalid-conditional-branch-empty-id' => [
 				'extraSettings' => [
 					'triggerType' => Constants::ANSWER_TYPE_DROPDOWN,

diff --git a/tests/Unit/Service/SubmissionServiceTest.php b/tests/Unit/Service/SubmissionServiceTest.php
@@ -1614,6 +1614,55 @@ public static function dataValidateSubmission() {
 				// Expected Result
 				'Question "Sub Q1" is required.',
 			],
+			'valid-conditional-checkbox-combination-trigger' => [
+				// Questions - conditional with multiple (checkbox) trigger
+				[
+					[
+						'id' => 100,
+						'type' => Constants::ANSWER_TYPE_CONDITIONAL,
+						'text' => 'Checkbox Conditional',
+						'isRequired' => true,
+						'extraSettings' => [
+							'triggerType' => Constants::ANSWER_TYPE_MULTIPLE,
+							'branches' => [
+								[
+									'id' => 'branch-combo1',
+									'conditions' => [['type' => 'options_combination', 'optionIds' => [10, 11]]],
+									'subQuestions' => [
+										[
+											'id' => 101,
+											'type' => 'short',
+											'text' => 'Combo 1 question',
+											'isRequired' => true,
+										]
+									]
+								],
+								[
+									'id' => 'branch-combo2',
+									'conditions' => [['type' => 'options_combination', 'optionIds' => [10]]],
+									'subQuestions' => []
+								]
+							]
+						],
+						'options' => [
+							['id' => 10],
+							['id' => 11],
+							['id' => 12]
+						]
+					]
+				],
+				// Answers - selecting options 10 and 11 activates branch-combo1
+				[
+					'100' => [
+						'trigger' => ['10', '11'],
+						'subQuestions' => [
+							'101' => ['Combo answer']
+						]
+					]
+				],
+				// Expected Result - valid
+				null,
+			],
 			'valid-conditional-no-branch-matched' => [
 				// Questions - conditional where trigger value doesn't match any branch
 				[
@@ -1720,6 +1769,37 @@ public static function dataValidateSubmission() {
 				// Expected Result
 				'Question "Conditional Q" is required.',
 			],
+			'invalid-conditional-checkbox-any-condition' => [
+				// Questions - a branch is active if any of its option combinations is selected
+				[
+					[
+						'id' => 100,
+						'type' => Constants::ANSWER_TYPE_CONDITIONAL,
+						'text' => 'Checkbox Conditional',
+						'isRequired' => false,
+						'extraSettings' => [
+							'triggerType' => Constants::ANSWER_TYPE_MULTIPLE,
+							'branches' => [
+								[
+									'id' => 'branch-1',
+									'conditions' => [
+										['type' => 'options_combination', 'optionIds' => [10, 11]],
+										['type' => 'options_combination', 'optionIds' => [12]],
+									],
+									'subQuestions' => [
+										['id' => 101, 'type' => 'short', 'text' => 'Combo question', 'isRequired' => true],
+									],
+								],
+							],
+						],
+						'options' => [['id' => 10], ['id' => 11], ['id' => 12]],
+					],
+				],
+				// Answers - only the second combination is selected
+				['100' => ['trigger' => ['12'], 'subQuestions' => []]],
+				// Expected Result
+				'Question "Combo question" is required.',
+			],
 			'invalid-conditional-answer-for-inactive-branch' => [
 				// Questions - two branches with one subquestion each
 				[