How to add the menu or button on the MDIChildFrame of the caption

Dear Sirs,
I have a MDIChildFrame with the wx.SYSTEM_MENU.When I press the close_box,I don’t want the MDIChildFrame to be closed,I want it to be hided,but Idon’t know how to change the evt and what evt to trigger the close.
the other question,I have a MDIChildFrame only with the wx.CAPTION ,I want to add button on the CAPTION,how should I do?
Thank You!