Dropdown Selection Problem

In webdynpro when I select dropdown by typing a letter, usually the curser is moved to first word of that particular letter, and after selecting some value, dropdown value is get selected. But now by default when type a letter, first word in my dropdown with that letter, got selected, without moving the curser to that position. I am facing this problem, only when I associate some action with Onselect event.

For example.

My dropdown is

April

May

June

July

August

Curser kept on dropdown, and when I type J, the position move to June and the value is not get selected. I have the option to move to July and then when I select July, the value is moved to context.

But now when I type J itself, June gets selected and the value is moved to the conext.

My development is on WebAS6.4 SP19. I am developing a stand alone webdynpro application. I am not using EP. Also I am using custom theme in my server for webdynpro applications. I have tried with DDBI and DDBK. I facing the same problem with both.

Is there any solution to resolve this issue?

Thanks in Advance.

Bala