When the Preference "Show drawings as children" is activated, drawings are shown as children of a 3d model. However, all drawings are shown, also the drawings where the 3d model only is a component. This means that for standard components like screws hundreds of drawings could be shown. Also this makes queries very slow. When i do an "expand all" of a large assy with the preference activated this can take hours or leads to out of memory errors.
Suggestion: introduce an extra option that only shows the drawings where the 3d model is the owner. This gives more usefuil information and drastically reduces query times (in the mentioned example seconds instead of hours!)