Engine Dialog: fix various signal connections

connect/disconnect button was connected multiple times
Also the button allowed to start a backend with
invalid settings (after changing backend).

Q: does “Connect to” make sense? It’s redundant with 
“Apply”.

1 files changed, 8 insertions, 2 deletions

diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index 0ce413246d..35876d5c37 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -298,6 +298,10 @@ EngineControl::EngineControl ()
 	output_channels.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
 
 	notebook.signal_switch_page().connect (sigc::mem_fun (*this, &EngineControl::on_switch_page));
+
+	connect_disconnect_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::connect_disconnect_click));
+	connect_disconnect_button.set_no_show_all();
+
 }
 
 void
@@ -512,8 +516,6 @@ EngineControl::build_no_control_notebook ()
 		row++;
 	}
 
-	connect_disconnect_button.signal_clicked().connect (sigc::mem_fun (*this, &EngineControl::connect_disconnect_click));
-
 	basic_packer.attach (connect_disconnect_button, 0, 2, row, row+1, FILL, AttachOptions (0));
 	row++;
 }
@@ -759,6 +761,8 @@ EngineControl::backend_changed ()
 		}
 	}
 
+	connect_disconnect_button.hide();
+
 	midi_option_changed();
 
 	started_at_least_once = false;
@@ -2109,6 +2113,7 @@ EngineControl::engine_running ()
 	sample_rate_combo.set_sensitive (true);
 
 	connect_disconnect_button.set_label (string_compose (_("Disconnect from %1"), backend->name()));
+	connect_disconnect_button.show();
 
 	started_at_least_once = true;
 }
@@ -2121,6 +2126,7 @@ EngineControl::engine_stopped ()
 
 	buffer_size_combo.set_sensitive (false);
 	connect_disconnect_button.set_label (string_compose (_("Connect to %1"), backend->name()));
+	connect_disconnect_button.show();
 
 	sample_rate_combo.set_sensitive (true);
 	buffer_size_combo.set_sensitive (true);