Allow deletion of processors in editor_mixer_strip by pointing and pressing Delete

This had to be hacked because the editor_mixer strip is on the editor and doesnt respond to mixer keybindings.
Also force the gain intry to lose focus if the user leaves the mixer strip.  this will probably solve some long-standing complaints.  although perhaps a more elegant solution is possible.

gtk2_ardour/editor.h

@@ -308,6 +308,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	void set_selected_mixer_strip (TimeAxisView&);
 	void mixer_strip_width_changed ();
 	bool mixer_strip_enter_event ( GdkEventCrossing * );
+	bool mixer_strip_leave_event ( GdkEventCrossing * );
 	void hide_track_in_display (TimeAxisView* tv, bool apply_to_selection = false);
 
 	/* nudge is initiated by transport controls owned by ARDOUR_UI */

gtk2_ardour/editor_mixer.cc

@@ -185,6 +185,7 @@ Editor::create_editor_mixer ()
 	current_mixer_strip->set_embedded (true);
 	
 	current_mixer_strip->signal_enter_notify_event().connect (sigc::mem_fun(*this, &Editor::mixer_strip_enter_event ));
+	current_mixer_strip->signal_leave_notify_event().connect (sigc::mem_fun(*this, &Editor::mixer_strip_leave_event ));
 
 }
 
@@ -195,6 +196,17 @@ Editor::mixer_strip_enter_event (GdkEventCrossing *ev)
 	return false;
 }
 
+bool
+Editor::mixer_strip_leave_event (GdkEventCrossing *ev)
+{
+	//if we have moved outside our strip, but not into a child view, then deselect ourselves
+	if ( !(ev->detail == GDK_NOTIFY_INFERIOR) ) {
+		current_mixer_strip->set_selected(false);
+	}
+	
+	return false;
+}
+
 void
 Editor::set_selected_mixer_strip (TimeAxisView& view)
 {

gtk2_ardour/editor_ops.cc

@@ -76,6 +76,7 @@
 #include "interthread_progress_window.h"
 #include "keyboard.h"
 #include "midi_region_view.h"
+#include "mixer_strip.h"
 #include "mouse_cursors.h"
 #include "normalize_dialog.h"
 #include "patch_change_dialog.h"
@@ -3731,7 +3732,13 @@ Editor::bounce_range_selection (bool replace, bool enable_processing)
 void
 Editor::delete_ ()
 {
-	cut_copy (Delete);
+	//special case: if the user is pointing in the editor/mixer strip, they may be trying to delete a plugin.
+	//we need this because the editor-mixer strip is in the editor window, so it doesn't get the bindings from the mix window
+	//TODO:  perhaps someday we need to accomodate the other bindings such as mute, solo, etc.
+	if ( current_mixer_strip && current_mixer_strip->is_selected() )
+		current_mixer_strip->delete_processors ();
+	else
+		cut_copy (Delete);
 }
 
 /** Cut selected regions, automation points or a time range */

gtk2_ardour/mixer.bindings

@@ -14,6 +14,7 @@
      <Binding key="Primary-c" action="Mixer/copy-processors"/>
      <Binding key="Primary-v" action="Mixer/paste-processors"/>
      <Binding key="Delete" action="Mixer/delete-processors"/>
+     <Binding key="Backspace" action="Mixer/delete-processors"/>
      <Binding key="Return" action="Mixer/toggle-processors"/>
      <Binding key="Primary-a" action="Mixer/select-all-processors"/>
      <Binding key="Slash" action="Mixer/ab-plugins"/>

gtk2_ardour/mixer_strip.cc

@@ -1612,6 +1612,11 @@ MixerStrip::set_selected (bool yn)
 		global_frame.set_name ("MixerStripFrame");
 	}
 	global_frame.queue_draw ();
+	
+	if (!yn) {  //if deselected, clear keyboard focus in the gain display.  this is cheesy but fixes a longstanding bug
+		gpm.gain_display.set_sensitive(false);
+		gpm.gain_display.set_sensitive(true);
+	}
 }
 
 void

gtk2_ardour/mixer_strip.h

@@ -131,6 +131,7 @@ class MixerStrip : public RouteUI, public Gtk::EventBox
 	void ab_plugins ();
 
 	void set_selected(bool yn);
+	bool is_selected() {return _selected;}
 
   protected:
 	friend class Mixer_UI;