From a5ccfb2f993b7ea0106775ceb23ff5a202de52a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mantas=20=C5=A0imk=C5=ABnas?=
 <msimkunas@users.noreply.github.com>
Date: Tue, 12 May 2020 20:30:03 +0300
Subject: [PATCH] Documented indeterminate checkboxes (#5068)

---
 modules/system/assets/ui/docs/checkbox.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/modules/system/assets/ui/docs/checkbox.md b/modules/system/assets/ui/docs/checkbox.md
index d4276d9cd..7167d823b 100644
--- a/modules/system/assets/ui/docs/checkbox.md
+++ b/modules/system/assets/ui/docs/checkbox.md
@@ -47,6 +47,15 @@ Allows a user to select from a list of binary options.
         </div>
     </div>
 
+### Indeterminate checkboxes
+
+    <div class="checkbox custom-checkbox is-indeterminate">
+        <input name="checkbox" value="1" type="checkbox" id="checkbox1" data-checked="1" />
+        <label for="checkbox1">Checkbox</label>
+    </div>
+
+The `data-checked` attribute may have one of three values: 0 (off), 1 (indeterminate) or 2 (on).
+
 ### Radio
 
     <div class="radio custom-radio">