Why does an embedded form not respond to arrow keys?

I am building a simple plugin framework in Delphi (XE) where the plugins are forms than can be optionally embedded into a TabSheet on a main application. There are examples on the web that explain how to do the embedding, for example: http://delphi.about.com/od/adptips2005/a/bltip0305_5.htm. I have tried this myself and it appears successful. However I find that if I put a TMemo on the embedded form, the arrow keys do not work on the embedded TMemo, ie the cursor on the TMemo will not move. Other keys such as backspace, delete, Ctrl-V etc and alphanumeric keys work as expected (The TAB will not traverse the controls in the embedded form either). A TMemo on the main application works fine. Any idea why the TMemo in the embedde开发者_开发百科d form will not respond to the arrow keys?

I in counter the same way before and i use the Form.Preview := True to inherit the key activity to make it global. try to see this example it be useful for you.

The problem lies with the plugin system I build (which remains to be identified) not with the embedding itself.