This gets used in the "Tools" -> "XML Filter Settings" dialog
in Writer when selecting multiple rows in the tree view,
then clicking the "Save as Package" button.
The result with SAL_VCL_QT_USE_WELDED_WIDGETS=1 and the
qt6 VCL plugin in XMLFilterSettingsDialog::onSave looks
as expected with this change in place (variables `aFilters`
and `nFilters` contain the selected filters and total
count of these when observed with a breakpoint after the call to
`m_xFilterListBox->selected_foreach`).
The method still triggers an assert later in a WIP
branch where support for that dialog is declared,
because `QtInstanceWindow::GetXWindow` is called,
but not implemented yet.
Change-Id: Iab47f391106132b5a6ee03fd2ad1902d493c0999
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178070
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>