tdf#130449 allow gdk_window_move_to_rect to try GDK_ANCHOR_SLIDE

as well as GDK_ANCHOR_FLIP if the window placement will put part of the
floating window off screen

Change-Id: I6b76df371048865cb4b1befea5ba34b38336944e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/96482
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/vcl/unx/gtk3/gtk3gtkframe.cxx b/vcl/unx/gtk3/gtk3gtkframe.cxx
index 62307f5..2ddcb832 100644
--- a/vcl/unx/gtk3/gtk3gtkframe.cxx
+++ b/vcl/unx/gtk3/gtk3gtkframe.cxx
@@ -2984,7 +2984,7 @@
                           static_cast<int>(aFloatRect.GetWidth()), static_cast<int>(aFloatRect.GetHeight())};

        GdkWindow* gdkWindow = gtk_widget_get_window(pThis->m_pWindow);
        window_move_to_rect(gdkWindow, &rect, rect_anchor, menu_anchor, GDK_ANCHOR_FLIP, 0, 0);
        window_move_to_rect(gdkWindow, &rect, rect_anchor, menu_anchor, static_cast<GdkAnchorHints>(GDK_ANCHOR_FLIP | GDK_ANCHOR_SLIDE), 0, 0);
    }
}