diff --git a/timeline/src/Timeline.C b/timeline/src/Timeline.C
index 99abcdf..2999f9d 100644
--- a/timeline/src/Timeline.C
+++ b/timeline/src/Timeline.C
@@ -476,7 +476,7 @@ Timeline::menu_cb ( Fl_Menu_ *m )
     {
         nframes_t f = transport->frame;
 
-        if ( prev_line( &f ) )
+        if ( f > 0 && prev_line( &f ) )
             transport->locate( f );
     }
     else if ( ! strcmp( picked, "Playhead right beat" ) )
@@ -490,7 +490,7 @@ Timeline::menu_cb ( Fl_Menu_ *m )
     {
         nframes_t f = transport->frame;
 
-        if ( prev_line( &f, true ) )
+        if ( f > 0 && prev_line( &f, true ) )
             transport->locate( f );
     }
     else if ( ! strcmp( picked, "Playhead right bar" ) )
@@ -890,7 +890,12 @@ Timeline::next_line ( nframes_t *frame, bool bar ) const
 
     nearest_line_arg n = { when, JACK_MAX_FRAMES, bar };
 
-    render_tempomap( when, x_to_ts( w() ), prev_next_line_cb, &n );
+    nframes_t length = sample_rate() * 60;
+
+    if (length > (JACK_MAX_FRAMES - when))
+      length = JACK_MAX_FRAMES - when;
+
+    render_tempomap( when, length, prev_next_line_cb, &n );
 
     if ( n.closest == (nframes_t)-1 )
         return false;
@@ -911,7 +916,14 @@ Timeline::prev_line ( nframes_t *frame, bool bar ) const
 
     nearest_line_arg n = { when, 0, bar };
 
-    render_tempomap( xoffset, when - xoffset, prev_next_line_cb, &n );
+    nframes_t start = 0;
+
+    /** Assume that the tempo will not be less than 1.0 bpm */
+    start = when - sample_rate() * 60;
+    if ((int)start < 0)
+        start = 0;
+
+    render_tempomap( start, when - start, prev_next_line_cb, &n );
 
     if ( n.closest == JACK_MAX_FRAMES )
         return false;