Zoom not bounded in Resource Usage view. A patch for this exists (as part of
another patch set) if anyone wants the code. Needs to have planner-ttable-view.c
changed to have a new function....

static void	   ttable_view_update_zoom_sensitivity (PlannerView *view);

which is...
static void
ttable_view_update_zoom_sensitivity (PlannerView *view)
{
	gboolean in, out;

	planner_ttable_chart_can_zoom (view->priv->chart,
				 &in,
				 &out);

	bonobo_ui_component_freeze (view->ui_component, NULL);
	
	bonobo_ui_component_set_prop (view->ui_component, 
				      "/commands/ZoomIn",
				      "sensitive", in ? "1" : "0", 
				      NULL);

	bonobo_ui_component_set_prop (view->ui_component, 
				      "/commands/ZoomOut",
				      "sensitive", out ? "1" : "0", 
				      NULL);
	
	bonobo_ui_component_thaw (view->ui_component, NULL);
}

and call this at end of...
activate()
ttable_view_zoom_out_cb()
ttable_view_zoom_in_cb()
ttable_view_zoom_to_fit_cb()


Note that planner_ttable_chart_can_zoom() already exists.