Maximize button for resizable instruments

Show the maximize button for resizable instruments.

Most other changes have the character of refactorings and code
reorganizations.

Remove the negation in the if condition for resizable instruments to
make the code better readable.

Only manipulate the system menu if the instrument is not resizable.

Add a TODO to the special code that sets a size.

src/gui/instrument/InstrumentTrackWindow.cpp

@@ -285,24 +285,30 @@ InstrumentTrackWindow::InstrumentTrackWindow( InstrumentTrackView * _itv ) :
 
 	QMdiSubWindow* subWin = getGUI()->mainWindow()->addWindowedWidget( this );
 	Qt::WindowFlags flags = subWin->windowFlags();
-	if (!m_instrumentView->isResizable()) {
-		flags |= Qt::MSWindowsFixedSizeDialogHint;
-		// any better way than this?
-	} else {
-		subWin->setMaximumSize(m_instrumentView->maximumHeight() + 12, m_instrumentView->maximumWidth() + 208);
-		subWin->setMinimumSize( m_instrumentView->minimumWidth() + 12, m_instrumentView->minimumHeight() + 208);
+
+	if (m_instrumentView->isResizable())
+	{
+		// TODO As of writing SlicerT is the only resizable instrument. Is this code specific to SlicerT?
+		const auto extraSpace = QSize(12, 208);
+		subWin->setMaximumSize(m_instrumentView->maximumSize() + extraSpace);
+		subWin->setMinimumSize(m_instrumentView->minimumSize() + extraSpace);
+
+		flags |= Qt::WindowMaximizeButtonHint;
 	}
-	flags &= ~Qt::WindowMaximizeButtonHint;
-	subWin->setWindowFlags( flags );
+	else
+	{
+		flags |= Qt::MSWindowsFixedSizeDialogHint;
+		flags &= ~Qt::WindowMaximizeButtonHint;
 
+		// Hide the Size and Maximize options from the system menu since the dialog size is fixed.
+		QMenu * systemMenu = subWin->systemMenu();
+		systemMenu->actions().at(2)->setVisible(false); // Size
+		systemMenu->actions().at(4)->setVisible(false); // Maximize
+	}
 
-	// Hide the Size and Maximize options from the system menu
-	// since the dialog size is fixed.
-	QMenu * systemMenu = subWin->systemMenu();
-	systemMenu->actions().at( 2 )->setVisible( false ); // Size
-	systemMenu->actions().at( 4 )->setVisible( false ); // Maximize
+	subWin->setWindowFlags(flags);
 
-	subWin->setWindowIcon( embed::getIconPixmap( "instrument_track" ) );
+	subWin->setWindowIcon(embed::getIconPixmap("instrument_track"));
 	subWin->hide();
 }