Сообщения, не документированные Microsoft
| WM_ALTTABACTIVE | WM_ISACTIVEICON |
| WM_BEGINDRAG | WM_LBTRACKPOINT |
| WM_CONVERTREQUEST | WM_NEXTMENU |
| WM_CONVERTRESULT | WM_QUERYDROPOBJECT |
| WM_DRAGLOOP | WM_QUERYPARKICON |
| WM_DRAGMOVE | WM_SETHOTKEY |
| WM_DRAGSELECT | WM_SETVISIBLE |
| WM_DROPOBJECT | WM_SIZEWAIT |
| WM_ENTERMENULOOP | WM_SYNCPAINT |
| WM_ENTERSIZEMOVE | WM_SYNCSTACK |
| WM_EXITMENULOOP | WM_SYSTIMER |
| WM_EXITSIZEMOVE | WM_TESTING |
| WM_FILESYSCHANGE | WM_YOMICHAR |
| WM_GETHOTKEY |