Index: gtk2_ardour/tempo_lines.cc
===================================================================
--- gtk2_ardour/tempo_lines.cc	(revision 6993)
+++ gtk2_ardour/tempo_lines.cc	(working copy)
@@ -136,6 +136,9 @@
 			break;
 
 		case ARDOUR::TempoMap::Beat:
+//// HACK BM. Don't draw tempo lines. Workaround for zoom assert
+			break; 
+//// End Hack BM
 			if ((*i).beat == 1) {
 				color = ARDOUR_UI::config()->canvasvar_MeasureLineBar.get();
 			} else {