2.1.2 EXSTYLE statement

This statement allows the application developer to designate one of the extended (WS_EX_xxx) styles for a dialog or control window. There are three methods, depending upon what is needed.

It may be placed just below the DIALOG statement to apply to the dialog window (like the CAPTION or STYLE statements). EXSTYLE <flags>
It may be placed on the DIALOG statement with the memory flags. FOOBAR DIALOG [MemFlags...] [EXSTYLE=<flags>] x, y, dx, dy
It may also be placed on the individual CONTROL, PUSHBUTTON, LTEXT, and other statements at the end of the statement. AUTOCHECKBOX "autocheckbox", id, x, y, dx, dy [styleflags][exstyleflags]