This example uses the WinSetCapture call to capture the mouse until the button is released. The user has selected a specific object with mouse button 2.

#define INCL_WININPUT
#include <OS2.H>
HWND hwnd;
USHORT msg;
WinSetCapture(hwnd,HWND_DESKTOP);
  switch (msg) {
    case WM_BUTTON2DOWN:

    /*******************************************************************/
    /* An object has been picked. Set the mouse capture until          */
    /* a 'button up' message is detected.                              */
    /*******************************************************************/
      if (hwnd != WinQueryFocus(HWND_DESKTOP)){
          WinSetFocus(HWND_DESKTOP, hwnd);
      }
      WinSetCapture(HWND_DESKTOP, hwnd);
      break;
   }