Added SubWindow class to compensate for incorrect behavior of normalGeometry() method on X11

src/gui/CMakeLists.txt

@@ -24,6 +24,7 @@ SET(LMMS_SRCS
 	gui/PluginBrowser.cpp
 	gui/SetupDialog.cpp
 	gui/StringPairDrag.cpp
+	gui/SubWindow.cpp
 	gui/TimeLineWidget.cpp
 	gui/ToolPluginView.cpp
 	gui/TrackContainerView.cpp

src/gui/SubWindow.cpp

@@ -0,0 +1,67 @@
+/*
+ * SubWindow.cpp - Implementation of QMdiSubWindow that correctly tracks
+ *   the geometry that windows should be restored to.
+ *   Workaround for https://bugreports.qt.io/browse/QTBUG-256
+ *
+ * Copyright (c) 2015 Colin Wallace <wallace.colin.a@gmail.com>
+ *
+ * This file is part of LMMS - http://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "SubWindow.h"
+
+#include <QMoveEvent>
+#include <QResizeEvent>
+#include <QWidget>
+
+
+SubWindow::SubWindow(QWidget *parent, Qt::WindowFlags windowFlags)
+  : QMdiSubWindow(parent, windowFlags)
+{
+	// initialize the tracked geometry to whatever Qt thinks the normal geometry currently is.
+	// this should always work, since QMdiSubWindows will not start as maximized
+	m_trackedNormalGeom = normalGeometry();
+}
+
+QRect SubWindow::getTrueNormalGeometry() const
+{
+	return m_trackedNormalGeom;
+}
+
+void SubWindow::moveEvent(QMoveEvent * event)
+{
+	QMdiSubWindow::moveEvent(event);
+	// if the window was moved and ISN'T minimized/maximized/fullscreen,
+	//   then save the current position
+	if (!isMaximized() && !isMinimized() && !isFullScreen())
+	{
+		m_trackedNormalGeom.moveTopLeft(event->pos());
+	}
+}
+
+void SubWindow::resizeEvent(QResizeEvent * event)
+{
+	QMdiSubWindow::resizeEvent(event);
+	// if the window was resized and ISN'T minimized/maximized/fullscreen,
+	//   then save the current size
+	if (!isMaximized() && !isMinimized() && !isFullScreen())
+	{
+		m_trackedNormalGeom.setSize(event->size());
+	}
+}