saw this in passing checking something else

==12972==    at 0x6DEF40B0: rtl::Reference<PlacesListBox>::get() const (ref.hxx:169)
==12972==    by 0x6DEEF221: VclPtr<PlacesListBox>::operator bool() const (vclptr.hxx:189)
==12972==    by 0x6DEED3DA: CustomContainer::GetFocus() (iodlg.cxx:429)
==12972==    by 0xD9EC83B: vcl::Window::CompatGetFocus() (window.cxx:3734)
==12972==    by 0xD93A604: vcl::Window::ImplGrabFocus(GetFocusFlags) (mouse.cxx:383)

...

==12972==  Address 0x2e4b4690 is 288 bytes inside a block of size 424 free'd
==12972==    at 0x4C2D22A: operator delete(void*) (vg_replace_malloc.c:576)
==12972==    by 0x6DED9F14: SvtFileDialog::dispose() (iodlg.cxx:518)
==12972==    by 0xDB04B1F: OutputDevice::disposeOnce() (outdev.cxx:161)
==12972==    by 0x6DED1954: VclPtr<SvtFileDialog_Base>::disposeAndClear() (vclptr.hxx:208)

Change-Id: I702eab8dbcf07885e4a3415ace6706c25854174e
(cherry picked from commit 5b342e10)