Related: tdf#124148 null-deref on clicking inside empty listbox

since...

commit ce9dab8c
Date:   Thu Mar 28 17:43:29 2019 +0900

    tdf#124148 add configurable margin for the listbox pop-up list

Change-Id: Id0bedb86f4fb74aff230d65f1e4371959814fd0f
Reviewed-on: https://gerrit.libreoffice.org/70151
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

vcl/source/control/imp_listbox.cxx

@@ -810,9 +810,11 @@ sal_Int32 ImplListBoxWindow::GetEntryPosForPoint( const Point& rPoint ) const
 
     sal_Int32 nSelect = mnTop;
     const ImplEntryType* pEntry = mpEntryList->GetEntryPtr( nSelect );
-    long nEntryHeight = pEntry->getHeightWithMargin();
-    while( pEntry && rPoint.Y() > nEntryHeight + nY )
+    while (pEntry)
     {
+        long nEntryHeight = pEntry->getHeightWithMargin();
+        if (rPoint.Y() <= nEntryHeight + nY)
+            break;
         nY += nEntryHeight;
         pEntry = mpEntryList->GetEntryPtr( ++nSelect );
     }