37315 - HTMLViewer objects not destructing when Window closes on Win32

[Mike_D]

This looks to be a long-standing bug, but could account for non-trivial memory leaks on Win32 builds.

<https://xojo.com/issue/37315>

[Greg_O_Lone]

Native or Webkit?

[Mike_D]

Native HTMLViewer. Tested under Windows 7 64 bit.