The EM_REQUESTRESIZE message forces a rich edit control to send an EN_REQUESTRESIZE notification message to its parent window.
EM_REQUESTRESIZE
wParam = 0;
lParam = 0;
No return value.
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, EN_REQUESTRESIZE, WM_SIZE