Fix off by 1 error in wxGenericListCtrl::HitTest().

Account for the header height if the header is present.

Closes #15063.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73563 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/listctrl.cpp

@@ -4144,6 +4144,10 @@ long wxListMainWindow::HitTest( int x, int y, int &flags ) const
 
     if ( InReportView() )
     {
+        // Account for the header height if it's present.
+        if ( HasHeader() )
+            y -= GetListCtrl()->m_headerWin->GetSize().y + 1;
+
         size_t current = y / GetLineHeight();
         if ( current < count )
         {