Change the Desktop font size (normal, large, extra large)

Hallo,
I’m writing a little application that has to change the screen appearance font size (normal large and extra large) at run-time.
I have already read several posts about how to get the DPI setting back or change it. The problem is how to propagate this change to the system.

Sending a WM_SETTINGCHANGE message with SETNONCLIENTMETRICS
WPARAM affects only the Desktop Icons. The taskbar and start menu are not affected.

Code:

---

SendMessageTimeout HWND_BROADCAST, _
  WM_SETTINGCHANGE, _
  SPI_SETNONCLIENTMETRICS, _
  0&, _
  SMTO_ABORTIFHUNG, _
  10000&,
  dw_Result

---

Thanks a lot for helping


James