The EM_SELECTIONTYPE message determines the selection type for a rich edit control.
EM_SELECTIONTYPE 
wParam = 0; 
lParam = 0; 
 Returns SEL_EMPTY if the selection is empty, or one or more of the following values:
| Value | Contents of the selection | 
|---|---|
| SEL_TEXT | Text | 
| SEL_OBJECT | At least one OLE object | 
| SEL_MULTICHAR | More than one character of text | 
| SEL_MULTIOBJECT | More than one OLE object | 
This message is useful during WM_SIZE processing for the parent of a bottomless rich edit control.
  Windows NT: Requires version 3.51 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in richedit.h.
Rich Edit Controls Overview, Rich Edit Messages, WM_SIZE