Constrain Samplerate selection when session is loaded

Ardour does not allow to change the rate of a session itself.

diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index ffbf787b6acd8cd15b36ab2e4b893d2a1300a652..8a6c42fd8c79bdb11771d4463dcfe96322fa65b3 100644 (file)
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -852,11 +852,17 @@ EngineControl::update_sensitivity ()
        }
 
        if (get_popdown_string_count (sample_rate_combo) > 0) {
+               bool allow_to_set_rate = false;
                if (!ARDOUR::AudioEngine::instance()->running()) {
-                       sample_rate_combo.set_sensitive (true);
-               } else {
-                       sample_rate_combo.set_sensitive (false);
+                       if (!ARDOUR_UI::instance()->session_loaded) {
+                               // engine is not running, no session loaded -> anything goes.
+                               allow_to_set_rate = true;
+                       } else if (_desired_sample_rate > 0 && get_rate () != _desired_sample_rate) {
+                               // only allow to change if the current setting is not the native session rate.
+                               allow_to_set_rate = true;
+                       }
                }
+               sample_rate_combo.set_sensitive (allow_to_set_rate);
        } else {
                sample_rate_combo.set_sensitive (false);
                valid = false;