http://stackoverflow.com/questions/8053545/in-delphi-xe2-firemonkey-how-do-i-change-the-color-of-a-button-after-pressing

1. Select 'Edit custom style ...' in the Right mouse button menu from a button.
2. Change the Fill.Color property from the TRectangle items under the background:TRectangle
3. Apply and Close Stylebook
4. Clear button.stylelookup
5. Change the button.stylelookup in your buttonclick to the new create style, when you didn't change the name its Button1Style1

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好象漏掉了要加某个层 layout 的步骤.(?)