When minimizing, my dialog box is overwriting my icon!

In the WM_MINMAXFRAME message hide the offending control.

    case WM_MINMAXFRAME:
      {
        PSWP pswp; /* pos change structure */

        /* hide list box when minimized so it doesn't overwrite icon */
        pswp = PVOIDFROMMP( mp1 );
        WinShowWindow(
          WinWindowFromID( hwnd, IDD_FILES ),
          !(pswp->fs & SWP_MINIMIZE)
        );
      }
      break;