diff --git a/src/System.Windows.Forms/src/System/Windows/Forms/ToolStripDropDownItem.cs b/src/System.Windows.Forms/src/System/Windows/Forms/ToolStripDropDownItem.cs
index ac4ad79adce..7a25f206bae 100644
--- a/src/System.Windows.Forms/src/System/Windows/Forms/ToolStripDropDownItem.cs
+++ b/src/System.Windows.Forms/src/System/Windows/Forms/ToolStripDropDownItem.cs
@@ -542,12 +542,12 @@ protected internal override bool ProcessDialogKey(Keys keyData)
         {
             Keys keyCode = (Keys)keyData & Keys.KeyCode;
 
+            // Items on the overflow should have the same kind of keyboard handling as a toplevel
+            bool isTopLevel = (!IsOnDropDown || IsOnOverflow);
+
             if (HasDropDownItems)
             {
-                // Items on the overflow should have the same kind of keyboard handling as a toplevel
-                bool isToplevel = (!IsOnDropDown || IsOnOverflow);
-
-                if (isToplevel && (keyCode == Keys.Down || keyCode == Keys.Up || keyCode == Keys.Enter || (SupportsSpaceKey && keyCode == Keys.Space)))
+                if (isTopLevel && (keyCode == Keys.Down || keyCode == Keys.Up || keyCode == Keys.Enter || (SupportsSpaceKey && keyCode == Keys.Space)))
                 {
                     ToolStrip.s_selectionDebug.TraceVerbose("[SelectDBG ProcessDialogKey] open submenu from toplevel item");
 
@@ -561,7 +561,7 @@ protected internal override bool ProcessDialogKey(Keys keyData)
 
                     return true;
                 }
-                else if (!isToplevel)
+                else if (!isTopLevel)
                 {
                     // if we're on a DropDown - then cascade out.
                     bool menusCascadeRight = (((int)DropDownDirection & 0x0001) == 0);
@@ -583,6 +583,14 @@ protected internal override bool ProcessDialogKey(Keys keyData)
                     }
                 }
             }
+            else
+            {
+                // For a top-level item without sub-items: do nothing on Up/Down
+                if (isTopLevel && (keyCode == Keys.Down || keyCode == Keys.Up))
+                {
+                    return true;
+                }
+            }
 
             if (IsOnDropDown)
             {