Old icon replaces new icon on taskbar

WinSCP Version 4.2.6 Build 721 on Windows Vista.

It is a cosmetic bug only and very minor, but still annoying. When I open the internal text editor the new blue-green arrows icon on Windows' Taskbar gets replaced by the old icon. When I close the editor, the new icon reappears.

The old icon is not present in the WinSCP anymore. So this does not make any sense to me. Can you post a screenshot?