property Sign: Char;
The Sign property contains the character that will be shown as button image. You may choose custom font for this sign (SignFont property) and ever shift the sign accordingly to SignLeft and SignTop values.
If any bitmap image assigned to Glyph property, the CaptionButton will show the Glyph image instead of sign. In this case, values assigned to Sign, SignFont, SignLeft and SignTop properties will not be used.
SignFont, SignLeft, SignTop properties.