EN_PROTECTED and RichEdit - winapi

Question

The EN_PROTECTED notify message is sent to the parent of a rich edit control when there is an attempt to change "protected" text. This works for me and I've tried it with both richedit20 and richedit50. Any change to this protected text immediately triggers the EN_PROTECTED message. (Its a little complicated to set it up, but I've done that correctly.)
However, the documentation says if the parent returns non zero in response to the EN_PROTECTED message, it will prevent the protected text from being changed. This is not working for me.

Answer 1

I created a simple test dialog test app, using MFC - add the richedit control via the dialog edit, added a call to AfxInitRichEdit in the app initialization, added some code to the dialog to put text in the control (SetWindowText), selected the second word, applied the CFE_PROTECTED effects and then added a handler for EN_PROTECTED, in the handler i just set *pResult = TRUE.
When i ran the app it all worked fine; in that i was not able to modify the protected word but i could modify the rest of the text.
Unfortunately that really doesn't lead us to a conclusive reason as to why your code doesn't work - from what i can see it appears correct. Could be the version of the RichEdit20 dll i suppose - mine is 5.31.23.1224

Answer 2

(To Ruddy: code sample below if it reveals anything)
I eventually just did a PostMessage(hwnd,EM_UNDO...) from within the EN_PROTECTED handler and that is what I had to do to get this working for me. Returning TRUE never accomplished anything, though I know the handler was being hit and only for protected text. (the ODS function below is OutputDebugString).
But I've seen multiple examples on the web (most of them MFC however or sometimes DELPHI or something), where just returning TRUE in the EN_PROTECTED handler is said to prevent the change.
Actually, my Rich Edit Control was within a dialog but was being created with CreateWindowEx,so I tried intializing it through the RC file instead but it made no difference. (Some of the stuff I'm doing is kind of old school admittedly - sorry about that.) But actually I tried anything and everything to make EN_PROTECTED work like its documented and nothing worked - bizarre.
Oh well, EM_UNDO from within the EN_PROTECTED handler works, so guess I'll stick with that.
Original code (with the added EM_UNDO call):
case WM_NOTIFY: {
NM_UPDOWN* nm = (NM_UPDOWN*)lParam;
if ((nm->hdr.code == UDN_DELTAPOS) && (nm->hdr.idFrom == ID_UPD_ERR)) {
int e = nm->iPos + nm->iDelta;
SetWindowText(xml2->hStatMsg[1],xml2->ErrMsg(1,e));
SetWindowText(xml2->hStatMsg[2],xml2->ErrMsg(2,e));
}
else if (wParam == ID_EDIT_A) {
if (((LPNMHDR)lParam)->code == EN_PROTECTED) {
ODS("EN_PROTECTED", (int)((ENPROTECTED*)lParam)->msg);
PostMessage(xml2->hImgXml2,EM_UNDO,0,0);
return TRUE;
}
if (((LPNMHDR)lParam)->code == EN_SELCHANGE) {
anchors_adjsel(xml2->hImgXml2);
}
}
}
break;