How to change focused child on Window widget with key input?

Hi,
I have created dialog which have 2 dropbox and one button widget as child. When I call the createDialog routine. First child have focus. I want to change focused child with my button input. I have an buttonControl routine to send WM which key is pressed. The WM_KEY case is not triggered when I press the left button . if I press up or down key, dropdown widget changes its selected string. So I can understand that widget key reaction gets key inputs before WM_KEY. But when I press escape button. WM_KEY case triggered and I can close my window. However, WM_KEY case don't triggered When I press left or right button although widget have not left or right key reaction. How can I change focussed child with input key(GUI_SendKeyMsg,GUI_StoreKeyMsg).

Thanks in advance...

Best Regards.
Emin ATEŞ

I have found this thread on the forum. Sven(SEGGER-Schoenen) suggests custom callback function to deal with WM_KEY in the linked thread. I have tried for my application and it worked. Thank you Sven !