Don't use invalid info in the Timebase callback if no tempo map exists.

Timeline/Engine/Engine.C

@@ -174,6 +174,7 @@ Engine::timebase ( jack_transport_state_t, jack_nframes_t, jack_position_t *pos,
     position_info pi = timeline->solve_tempomap( pos->frame );
 
     pos->valid = JackPositionBBT;
+
     pos->beats_per_bar = pi.beats_per_bar;
     pos->beat_type = pi.beat_type;
     pos->beats_per_minute = pi.tempo;

Timeline/TLE.fl

@@ -161,7 +161,7 @@ Loggable::progress_callback( &TLE::progress_cb, this );} {}
   } {
     Fl_Window main_window {
       label Timeline
-      xywh {254 189 1025 770} type Double resizable xclass Non_DAW visible
+      xywh {174 117 1025 770} type Double resizable xclass Non_DAW visible
     } {
       Fl_Menu_Bar menubar {
         xywh {0 0 1024 25}
@@ -933,7 +933,7 @@ while ( _window->shown() )
   } {
     Fl_Window _window {
       label {Project info} open selected
-      xywh {394 254 520 625} type Double visible
+      xywh {215 260 520 625} type Double visible
     } {
       Fl_Value_Output {} {
         label {Sample Rate}

Timeline/Timeline.C

@@ -686,6 +686,11 @@ Timeline::render_tempomap( nframes_t start, nframes_t length, measure_line_callb
 
     BBT &bbt = pos.bbt;
 
+    /* default values */
+    pos.beat_type = 4;
+    pos.beats_per_bar = 4;
+    pos.tempo = 120.0;
+
     const nframes_t samples_per_minute = sample_rate() * 60;
 
     float bpm = 120.0f;