Посмотри эти стили в файле \borland\bcc55\include\
winuser.h:
...
/*
* Extended Window Styles
*/
#define WS_EX_DLGMODALFRAME 0x00000001L
#define WS_EX_NOPARENTNOTIFY 0x00000004L
#define WS_EX_TOPMOST 0x00000008L
#define WS_EX_ACCEPTFILES 0x00000010L
#define WS_EX_TRANSPARENT 0x00000020L
#if(WINVER >= 0x0400)
#define WS_EX_MDICHILD 0x00000040L
#define WS_EX_TOOLWINDOW 0x00000080L
#define WS_EX_WINDOWEDGE 0x00000100L
#define WS_EX_CLIENTEDGE 0x00000200L
#define WS_EX_CONTEXTHELP 0x00000400L
#define WS_EX_RIGHT 0x00001000L
#define WS_EX_LEFT 0x00000000L
#define WS_EX_RTLREADING 0x00002000L
#define WS_EX_LTRREADING 0x00000000L
#define WS_EX_LEFTSCROLLBAR 0x00004000L
#define WS_EX_RIGHTSCROLLBAR 0x00000000L
#define WS_EX_CONTROLPARENT 0x00010000L
#define WS_EX_STATICEDGE 0x00020000L
#define WS_EX_APPWINDOW 0x00040000L
#define WS_EX_OVERLAPPEDWINDOW (WS_EX_WINDOWEDGE | WS_EX_CLIENTEDGE)
#define WS_EX_PALETTEWINDOW (WS_EX_WINDOWEDGE | WS_EX_TOOLWINDOW | WS_EX_TOPMOST)
...