From df2ef7118cf7ac37a7f86a0c6d2d016080875997 Mon Sep 17 00:00:00 2001
From: Terry Aney <terry.aney@icloud.com>
Date: Wed, 19 Jan 2022 11:17:50 -0600
Subject: [PATCH] max-height/offsetHeight Calculation Issue, Fixes #2581

---
 js/bootstrap-select.js | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/js/bootstrap-select.js b/js/bootstrap-select.js
index f26b9e58c..067a68a6e 100644
--- a/js/bootstrap-select.js
+++ b/js/bootstrap-select.js
@@ -2118,6 +2118,16 @@
       if (doneButton) menu.appendChild(doneButton);
       newElement.appendChild(menu);
 
+      var newElementAnchor = $('a', $(li));
+      // Get 'visible' css items to restore after calculation is done
+      var newElementAnchorDisplay = newElementAnchor.css('display');
+      var newElementAnchorVisibility = newElementAnchor.css('visibility');
+      newElementAnchor.show(); // always make sure first item is shown, otherwise offsetHeight = 0
+      if (newElementAnchor.text() === '') {
+        // If blank, set text to non-breaking space otherwise offsetHeight = 8 (or some portion of full height)
+        newElementAnchor.text = '&nbsp;';
+      }
+
       document.body.appendChild(newElement);
 
       var liHeight = li.offsetHeight,
@@ -2170,6 +2180,9 @@
       this.sizeInfo.scrollBarWidth = scrollBarWidth;
       this.sizeInfo.selectHeight = this.$newElement[0].offsetHeight;
 
+      if (newElementAnchorDisplay !== undefined && newElementAnchorDisplay !== '') newElementAnchor.css('display', newElementAnchorDisplay);
+      if (newElementAnchorVisibility !== undefined && newElementAnchorVisibility !== '') newElementAnchor.css('visibility', newElementAnchorVisibility);
+
       this.setPositionData();
     },