The following new messages have been added to Windows 3.1:
| Message | Description |
| CB_FINDSTRINGEXACT | Finds a string in the list box of a combo box. |
| CB_GETDROPPEDCONTROLRECT | Retrieves the rectangle of the drop-down list box of a combo box. |
| CB_GETDROPPEDSTATE | Determines whether the list box of a combo box is visible. |
| CB_GETEXTENDEDUI | Determines whether a combo box has the extended interface. |
| CB_GETITEMHEIGHT | Retrieves the height of items in a combo box. |
| CB_SETEXTENDEDUI | Sets the default or extended user interface. |
| CB_SETITEMHEIGHT | Sets the height of items in a combo box. |
| EM_GETFIRSTVISIBLELINE | Retrieves the index of the top line in a multiline edit control. |
| EM_GETPASSWORDCHAR | Retrieves the password character displayed in an edit control. |
| EM_GETWORDBREAKPROC | Retrieves the wordwrap function for an edit control. |
| EM_SETREADONLY | Sets the read-only state of an edit control. |
| EM_SETWORDBREAKPROC | Provides custom word breaks in edit controls. |
| LB_FINDSTRINGEXACT | Finds a string in a list box. |
| LB_GETCARETINDEX | Retrieves the index of the list box item with the focus rectangle. |
| LB_GETITEMHEIGHT | Retrieves the height of items in a list box. |
| LB_SETCARETINDEX | Sets the focus rectangle in a list box. |
| LB_SETITEMHEIGHT | Sets the height of items in a list box. |
| STM_GETICON | Retrieves the icon handle associated with an icon control. |
| STM_SETICON | Associates an icon handle with an icon control. |
| WM_CHOOSEFONT_GETLOGFONT | Retrieves a LOGFONT structure for the Font common dialog box. |
| WM_COMMNOTIFY | Notifies a window about the status of its queues. |
| WM_DROPFILES | Indicates that a file has been dropped. |
| WM_PALETTEISCHANGING | Informs applications that an application is changing its palette. |
| WM_POWER | Indicates that the system is entering suspended mode. |
| WM_QUEUESYNC | Delimits computer-based training (CBT) messages. |
| WM_SYSTEMERROR | Indicates that a system error has occurred. |
| WM_WINDOWPOSCHANGED | Notifies a window that its size or position has changed. |
| WM_WINDOWPOSCHANGING | Notifies a window that its size or position is changing. |