InstrumentTrackView: use QMdiArea's window activation history

There's no need to implement an own (buggy) window activation history
for InstrumentTrackWindows. Use QMdiArea::subWindowList(...) instead.
Fixes buggy keyboard focus when switching between InstrumentTrackWindows.

include/InstrumentTrack.h

@@ -41,7 +41,6 @@
 
 class QLineEdit;
 template<class T> class QQueue;
-template<class T> class QStack;
 class ArpeggiatorView;
 class ChordCreatorView;
 class EffectRackView;
@@ -260,10 +259,7 @@ public:
 		return castModel<InstrumentTrack>();
 	}
 
-	static InstrumentTrackWindow * topLevelInstrumentTrackWindow()
-	{
-		return s_windowStack.isEmpty() ? NULL : s_windowStack.top();
-	}
+	static InstrumentTrackWindow * topLevelInstrumentTrackWindow();
 
 	QMenu * midiMenu()
 	{
@@ -294,7 +290,6 @@ private:
 	InstrumentTrackWindow * m_window;
 
 	static QQueue<InstrumentTrackWindow *> s_windowCache;
-	static QStack<InstrumentTrackWindow *> s_windowStack;
 
 	// widgets in track-settings-widget
 	trackLabelButton * m_tlb;

src/gui/MainWindow.cpp

@@ -1243,15 +1243,18 @@ void MainWindow::keyPressEvent( QKeyEvent * _ke )
 		case Qt::Key_Shift: m_keyMods.m_shift = true; break;
 		case Qt::Key_Alt: m_keyMods.m_alt = true; break;
 		default:
-			if( InstrumentTrackView::topLevelInstrumentTrackWindow() )
+		{
+			InstrumentTrackWindow * w =
+						InstrumentTrackView::topLevelInstrumentTrackWindow();
+			if( w )
 			{
-				InstrumentTrackView::topLevelInstrumentTrackWindow()->
-					pianoView()->keyPressEvent( _ke );
+				w->pianoView()->keyPressEvent( _ke );
 			}
 			if( !_ke->isAccepted() )
 			{
 				QMainWindow::keyPressEvent( _ke );
 			}
+		}
 	}
 }
 

src/tracks/InstrumentTrack.cpp

@@ -26,7 +26,6 @@
 #include <QtCore/QDir>
 #include <QtCore/QFile>
 #include <QtCore/QQueue>
-#include <QtCore/QStack>
 #include <QtGui/QApplication>
 #include <QtGui/QCloseEvent>
 #include <QtGui/QFileDialog>
@@ -876,7 +875,6 @@ Instrument * InstrumentTrack::loadInstrument( const QString & _plugin_name )
 
 
 QQueue<InstrumentTrackWindow *> InstrumentTrackView::s_windowCache;
-QStack<InstrumentTrackWindow *> InstrumentTrackView::s_windowStack;
 
 
 
@@ -987,6 +985,24 @@ InstrumentTrackView::~InstrumentTrackView()
 
 
 
+InstrumentTrackWindow * InstrumentTrackView::topLevelInstrumentTrackWindow()
+{
+	InstrumentTrackWindow * w = NULL;
+	foreach( QMdiSubWindow * sw,
+				engine::mainWindow()->workspace()->subWindowList(
+											QMdiArea::ActivationHistoryOrder ) )
+	{
+		if( sw->isVisible() && sw->widget()->inherits( "InstrumentTrackWindow" ) )
+		{
+			w = qobject_cast<InstrumentTrackWindow *>( sw->widget() );
+		}
+	}
+
+	return w;
+}
+
+
+
 // TODO: Add windows to free list on freeInstrumentTrackWindow. 
 // But, don't NULL m_window or disconnect signals.  This will allow windows 
 // that are being show/hidden frequently to stay connected.
@@ -994,12 +1010,6 @@ void InstrumentTrackView::freeInstrumentTrackWindow()
 {
 	if( m_window != NULL )
 	{
-		if( qFind( s_windowStack.begin(), s_windowStack.end(), m_window ) !=
-														s_windowStack.end() )
-		{
-			s_windowStack.erase(
-				qFind( s_windowStack.begin(), s_windowStack.end(), m_window ) );
-		}
 		m_lastPos = m_window->parentWidget()->pos();
 
 		if( configManager::inst()->value( "ui",
@@ -1102,23 +1112,12 @@ void InstrumentTrackView::dropEvent( QDropEvent * _de )
 
 void InstrumentTrackView::toggleInstrumentWindow( bool _on )
 {
-	InstrumentTrackWindow * w = getInstrumentTrackWindow();
-	w->toggleVisibility( _on );
+	getInstrumentTrackWindow()->toggleVisibility( _on );
 	
 	if( !_on )
 	{
 		freeInstrumentTrackWindow();
 	}
-	else
-	{
-		if( qFind( s_windowStack.begin(), s_windowStack.end(), w ) !=
-														s_windowStack.end() )
-		{
-			s_windowStack.erase(
-					qFind( s_windowStack.begin(), s_windowStack.end(), w ) );
-		}
-		s_windowStack.push( w );
-	}
 }