Nonclient-area messages are sent by Windows to create and maintain the nonclient area of an application's window. Normally, applications do not process these messages, but send them on to the DefWindowProc function for processing. The following list briefly describes each nonclient-area message:
| Message | Description | |
| WM_NCACTIVATE | Sent to a window when its caption bar or icon needs to be changed to indicate an active or inactive state. | |
| WM_NCCALCSIZE | Sent when the size of a window's client area needs to be calculated. | |
| WM_NCCREATE | Sent prior to the WM_CREATE message when a window is first created. | |
| WM_NCDESTROY | Sent after the WM_DESTROY message. | |
| WM_NCHITTEST | Sent to the window that contains the cursor (unless a window has captured the mouse). | |
| WM_NCLBUTTONDBLCLK | Sent to a window when the left mouse button is double-clicked while the cursor is in a nonclient area of the window. | |
| WM_NCLBUTTONDOWN | Sent to a window when the left mouse button is pressed while the cursor is in a nonclient area of the window. | |
| WM_NCLBUTTONUP | Sent to a window when the left mouse button is released while the cursor is in a nonclient area of the window. | |
| WM_NCMBUTTONDBLCLK | Sent to a window when the middle mouse button is double-clicked while the cursor is in a nonclient area of the window. | |
| WM_NCMBUTTONDOWN | Sent to a window when the middle mouse button is pressed while the cursor is in a nonclient area of the window. | |
| WM_NCMBUTTONUP | Sent to a window when the left mouse button is released while the cursor is in a nonclient area of the window. | |
| Message | Description | |
| WM_NCMOUSEMOVE | Sent to a window when the cursor is moved in a nonclient area of the window. | |
| WM_NCPAINT | Sent to a window when its border needs painting. | |
| WM_NCRBUTTONDBLCLK | Sent to a window when the right mouse button is double-clicked while the cursor is in a nonclient area of the window. | |
| WM_NCRBUTTONDOWN | Sent to a window when the right mouse button is pressed while the cursor is in a nonclient area of the window. | |
| WM_NCRBUTTONUP | Sent to a window when the right mouse button is released while the cursor is in a nonclient area of the window. |