richedit: Keep default char format on WM_SETFONT in plain text mode.

dlls/riched20/editor.c

@@ -3502,7 +3502,6 @@ LRESULT ME_HandleMessage(ME_TextEditor *editor, UINT msg, WPARAM wParam,
     CHARFORMAT2W fmt;
     HDC hDC;
     BOOL bRepaint = LOWORD(lParam);
-    ME_Cursor start;
 
     if (!wParam)
       wParam = (WPARAM)GetStockObject(SYSTEM_FONT);
@@ -3510,8 +3509,11 @@ LRESULT ME_HandleMessage(ME_TextEditor *editor, UINT msg, WPARAM wParam,
     hDC = ITextHost_TxGetDC(editor->texthost);
     ME_CharFormatFromLogFont(hDC, &lf, &fmt);
     ITextHost_TxReleaseDC(editor->texthost, hDC);
+    if (editor->mode & TM_RICHTEXT) {
+      ME_Cursor start;
       ME_SetCursorToStart(editor, &start);
       ME_SetCharFormat(editor, &start, NULL, &fmt);
+    }
     ME_SetDefaultCharFormat(editor, &fmt);
 
     ME_CommitUndo(editor);