diff --git a/Makefile b/Makefile
index 2153aaf..d9c7390 100644
--- a/Makefile
+++ b/Makefile
@@ -8,10 +8,11 @@ ALL = MotionCal imuread
 CC = gcc
 CXX = g++
 CFLAGS = -O2 -Wall -D$(OS)
+WXCONFIG = ~/wxwidgets/3.0.2.gtk2-opengl/bin/wx-config
+WXFLAGS = `$(WXCONFIG) --cppflags`
 CXXFLAGS = $(CFLAGS) `$(WXCONFIG) --cppflags`
 LDFLAGS =
 SFLAG = -s
-WXCONFIG = ~/wxwidgets/3.0.2.gtk2-opengl/bin/wx-config
 CLILIBS = -lglut -lGLU -lGL -lm
 MAKEFLAGS = --jobs=12
 
@@ -20,8 +21,9 @@ ALL = MotionCal.dmg
 CC = gcc-4.2
 CXX = g++-4.2
 CFLAGS = -O2 -Wall -D$(OS)
-CXXFLAGS = $(CFLAGS) `$(WXCONFIG) --cppflags`
 WXCONFIG = ~/wxwidgets/3.0.2.mac-opengl/bin/wx-config
+WXFLAGS = `$(WXCONFIG) --cppflags`
+CXXFLAGS = $(CFLAGS) `$(WXCONFIG) --cppflags`
 SFLAG = -s
 CLILIBS = -lglut -lGLU -lGL -lm
 VERSION = 0.01
@@ -32,6 +34,7 @@ CC = /usr/bin/clang
 CXX = /usr/bin/clang++
 CFLAGS = -O2 -Wall -DMACOSX
 WXCONFIG = wx-config
+WXFLAGS = `$(WXCONFIG) --cppflags`
 CXXFLAGS = $(CFLAGS) `$(WXCONFIG) --cppflags`
 SFLAG =
 CLILIBS = -lglut -lGLU -lGL -lm
@@ -39,14 +42,19 @@ VERSION = 0.01
 
 else ifeq ($(OS), WINDOWS)
 ALL = MotionCal.exe
-CC = i686-w64-mingw32-gcc
-CXX = i686-w64-mingw32-g++
-WINDRES = i686-w64-mingw32-windres
+#MINGW_TOOLCHAIN = i586-mingw32msvc
+MINGW_TOOLCHAIN = i686-w64-mingw32
+CC = $(MINGW_TOOLCHAIN)-gcc
+CXX = $(MINGW_TOOLCHAIN)-g++
+WINDRES = $(MINGW_TOOLCHAIN)-windres
 CFLAGS = -O2 -Wall -D$(OS)
-CXXFLAGS = $(CFLAGS) `$(WXCONFIG) --cppflags`
+WXFLAGS = `$(WXCONFIG) --cppflags`
+CXXFLAGS = $(CFLAGS) $(WXFLAGS)
 LDFLAGS = -static -static-libgcc
 SFLAG = -s
-WXCONFIG = ~/wxwidgets/3.0.2.mingw-opengl/bin/wx-config
+#WXCONFIG = ~/wxwidgets/3.0.2.mingw-opengl-i586/bin/wx-config
+#WXCONFIG = ~/wxwidgets/3.0.2.mingw-opengl/bin/wx-config
+WXCONFIG = ~/wxwidgets/3.1.0.mingw-opengl/bin/wx-config
 CLILIBS = -lglut32 -lglu32 -lopengl32 -lm
 MAKEFLAGS = --jobs=12
 
@@ -64,8 +72,8 @@ MotionCal.exe: resource.o gui.o portlist.o $(OBJS)
 	-pjrcwinsigntool $@
 	-./cp_windows.sh $@
 
-resource.o: resource.rs icon.ico
-	$(WINDRES) -o resource.o resource.rs
+resource.o: resource.rc icon.ico
+	$(WINDRES) $(WXFLAGS) -o resource.o resource.rc
 
 MotionCal.app: MotionCal Info.plist icon.icns
 	mkdir -p $@/Contents/MacOS
diff --git a/gui.cpp b/gui.cpp
index 9f074f2..037c924 100644
--- a/gui.cpp
+++ b/gui.cpp
@@ -46,9 +46,10 @@ void MyCanvas::OnPaint( wxPaintEvent& WXUNUSED(event) )
 
 void MyCanvas::InitGL()
 {
-	//printf("Init\n");
 	SetCurrent(*m_glRC);
 	visualize_init();
+	wxSizeEvent e = wxSizeEvent(GetSize());
+	OnSize(e);
 }
 
 
@@ -74,12 +75,18 @@ MyFrame::MyFrame(wxWindow *parent, wxWindowID id, const wxString &title,
     const wxPoint &position, const wxSize& size, long style) :
     wxFrame( parent, id, title, position, size, style )
 {
+	wxPanel *panel;
 	wxMenuBar *menuBar;
 	wxMenu *menu;
+	wxSizer *topsizer;
+	wxSizer *leftsizer, *middlesizer, *rightsizer;
 	wxSizer *hsizer, *vsizer, *calsizer;
 	wxStaticText *text;
 	int i, j;
 
+	topsizer = new wxBoxSizer(wxHORIZONTAL);
+	panel = new wxPanel(this);
+
 	menuBar = new wxMenuBar;
 	menu = new wxMenu;
 	menu->Append(ID_SENDCAL_MENU, wxT("Send Calibration"));
@@ -97,10 +104,9 @@ MyFrame::MyFrame(wxWindow *parent, wxWindowID id, const wxString &title,
 	menuBar->Append(menu, wxT("&Help"));
 	SetMenuBar(menuBar);
 
-	wxBoxSizer *topsizer = new wxBoxSizer(wxHORIZONTAL);
-	wxBoxSizer *leftsizer = new wxStaticBoxSizer(wxVERTICAL, this, "Communication");
-	wxBoxSizer *middlesizer = new wxStaticBoxSizer(wxVERTICAL, this, "Magnetometer");
-	wxBoxSizer *rightsizer = new wxStaticBoxSizer(wxVERTICAL, this, "Calibration");
+	leftsizer = new wxStaticBoxSizer(wxVERTICAL, panel, "Communication");
+	middlesizer = new wxStaticBoxSizer(wxVERTICAL, panel, "Magnetometer");
+	rightsizer = new wxStaticBoxSizer(wxVERTICAL, panel, "Calibration");
 
 	topsizer->Add(leftsizer, 0, wxALL | wxEXPAND | wxALIGN_TOP, 5);
 	topsizer->Add(middlesizer, 1, wxALL | wxEXPAND, 5);
@@ -108,9 +114,9 @@ MyFrame::MyFrame(wxWindow *parent, wxWindowID id, const wxString &title,
 
 	vsizer = new wxBoxSizer(wxVERTICAL);
 	leftsizer->Add(vsizer, 0, wxALL, 8);
-	text = new wxStaticText(this, wxID_ANY, "Port");
+	text = new wxStaticText(panel, wxID_ANY, "Port");
 	vsizer->Add(text, 0, wxTOP|wxBOTTOM, 4);
-	m_port_list = new wxComboBox(this, ID_PORTLIST, "",
+	m_port_list = new wxComboBox(panel, ID_PORTLIST, "",
 		wxDefaultPosition, wxDefaultSize, 0, NULL, wxCB_READONLY);
 	m_port_list->Append("(none)");
 	m_port_list->Append(SAMPLE_PORT_NAME); // never seen, only for initial size
@@ -118,107 +124,107 @@ MyFrame::MyFrame(wxWindow *parent, wxWindowID id, const wxString &title,
 	vsizer->Add(m_port_list, 1, wxEXPAND, 0);
 
 	vsizer->AddSpacer(8);
-	text = new wxStaticText(this, wxID_ANY, "Actions");
+	text = new wxStaticText(panel, wxID_ANY, "Actions");
 	vsizer->Add(text, 0, wxTOP|wxBOTTOM, 4);
-	m_button_clear = new wxButton(this, ID_CLEAR_BUTTON, "Clear");
+	m_button_clear = new wxButton(panel, ID_CLEAR_BUTTON, "Clear");
 	m_button_clear->Enable(false);
 	vsizer->Add(m_button_clear, 1, wxEXPAND, 0);
-	m_button_sendcal = new wxButton(this, ID_SENDCAL_BUTTON, "Send Cal");
+	m_button_sendcal = new wxButton(panel, ID_SENDCAL_BUTTON, "Send Cal");
 	vsizer->Add(m_button_sendcal, 1, wxEXPAND, 0);
 	m_button_sendcal->Enable(false);
 
 	vsizer = new wxBoxSizer(wxVERTICAL);
 	middlesizer->Add(vsizer, 1, wxEXPAND | wxALL, 8);
 
-	text = new wxStaticText(this, wxID_ANY, "");
+	text = new wxStaticText(panel, wxID_ANY, "");
 	text->SetLabelMarkup("<small><i>Ideal calibration is a perfectly centered sphere</i></small>");
 	vsizer->Add(text, 0, wxALIGN_CENTER_HORIZONTAL, 0);
 
 	int gl_attrib[20] = { WX_GL_RGBA, WX_GL_MIN_RED, 1, WX_GL_MIN_GREEN, 1,
 		WX_GL_MIN_BLUE, 1, WX_GL_DEPTH_SIZE, 1, WX_GL_DOUBLEBUFFER, 0};
-	m_canvas = new MyCanvas(this, wxID_ANY, gl_attrib);
-	m_canvas->SetMinSize(wxSize(400,400));
+	m_canvas = new MyCanvas(panel, wxID_ANY, gl_attrib);
+	m_canvas->SetMinSize(wxSize(480,480));
 	vsizer->Add(m_canvas, 1, wxEXPAND | wxALL, 0);
 
-
 	hsizer = new wxGridSizer(4, 0, 15);
 	middlesizer->Add(hsizer, 0, wxALL | wxALIGN_CENTER_HORIZONTAL, 5);
 	vsizer = new wxBoxSizer(wxVERTICAL);
 	hsizer->Add(vsizer, 1, wxALIGN_CENTER_HORIZONTAL);
-	text = new wxStaticText(this, wxID_ANY, "Gaps");
+	text = new wxStaticText(panel, wxID_ANY, "Gaps");
 	vsizer->Add(text, 1, wxALIGN_CENTER_HORIZONTAL);
-	m_err_coverage = new wxStaticText(this, wxID_ANY, "100.0%");
+	m_err_coverage = new wxStaticText(panel, wxID_ANY, "100.0%");
 	vsizer->Add(m_err_coverage, 1, wxALIGN_CENTER_HORIZONTAL);
 	vsizer = new wxBoxSizer(wxVERTICAL);
 	hsizer->Add(vsizer, 1, wxALIGN_CENTER_HORIZONTAL);
-	text = new wxStaticText(this, wxID_ANY, "Variance");
+	text = new wxStaticText(panel, wxID_ANY, "Variance");
 	vsizer->Add(text, 1, wxALIGN_CENTER_HORIZONTAL);
-	m_err_variance = new wxStaticText(this, wxID_ANY, "100.0%");
+	m_err_variance = new wxStaticText(panel, wxID_ANY, "100.0%");
 	vsizer->Add(m_err_variance, 1, wxALIGN_CENTER_HORIZONTAL);
 	vsizer = new wxBoxSizer(wxVERTICAL);
 	hsizer->Add(vsizer, 1, wxALIGN_CENTER_HORIZONTAL);
-	text = new wxStaticText(this, wxID_ANY, "Wobble");
+	text = new wxStaticText(panel, wxID_ANY, "Wobble");
 	vsizer->Add(text, 1, wxALIGN_CENTER_HORIZONTAL);
-	m_err_wobble = new wxStaticText(this, wxID_ANY, "100.0%");
+	m_err_wobble = new wxStaticText(panel, wxID_ANY, "100.0%");
 	vsizer->Add(m_err_wobble, 1, wxALIGN_CENTER_HORIZONTAL);
 	vsizer = new wxBoxSizer(wxVERTICAL);
 	hsizer->Add(vsizer, 1, wxALIGN_CENTER_HORIZONTAL);
-	text = new wxStaticText(this, wxID_ANY, "Fit Error");
+	text = new wxStaticText(panel, wxID_ANY, "Fit Error");
 	vsizer->Add(text, 1, wxALIGN_CENTER_HORIZONTAL);
-	m_err_fit = new wxStaticText(this, wxID_ANY, "100.0%");
+	m_err_fit = new wxStaticText(panel, wxID_ANY, "100.0%");
 	vsizer->Add(m_err_fit, 1, wxALIGN_CENTER_HORIZONTAL);
 
 	calsizer = new wxBoxSizer(wxVERTICAL);
 	rightsizer->Add(calsizer, 0, wxALL, 8);
-	text = new wxStaticText(this, wxID_ANY, "Magnetic Offset");
+	text = new wxStaticText(panel, wxID_ANY, "Magnetic Offset");
 	calsizer->Add(text, 0, wxTOP|wxBOTTOM, 4);
 	vsizer = new wxGridSizer(1, 0, 0);
 	calsizer->Add(vsizer, 1, wxLEFT, 20);
 	for (i=0; i < 3; i++) {
-		m_mag_offset[i] = new wxStaticText(this, wxID_ANY, "0.00");
+		m_mag_offset[i] = new wxStaticText(panel, wxID_ANY, "0.00");
 		vsizer->Add(m_mag_offset[i], 1);
 	}
-	text = new wxStaticText(this, wxID_ANY, "Magnetic Mapping");
+	text = new wxStaticText(panel, wxID_ANY, "Magnetic Mapping");
 	calsizer->Add(text, 0, wxTOP|wxBOTTOM, 4);
 	vsizer = new wxGridSizer(3, 0, 12);
 	calsizer->Add(vsizer, 1, wxLEFT, 20);
 	for (i=0; i < 3; i++) {
 		for (j=0; j < 3; j++) {
-			m_mag_mapping[i][j] = new wxStaticText(this, wxID_ANY,
+			m_mag_mapping[i][j] = new wxStaticText(panel, wxID_ANY,
 				((i == j) ? "+1.000" : "+0.000"));
 			vsizer->Add(m_mag_mapping[i][j], 1);
 		}
 	}
-	text = new wxStaticText(this, wxID_ANY, "Magnetic Field");
+	text = new wxStaticText(panel, wxID_ANY, "Magnetic Field");
 	calsizer->Add(text, 0, wxTOP|wxBOTTOM, 4);
-	m_mag_field = new wxStaticText(this, wxID_ANY, "0.00");
+	m_mag_field = new wxStaticText(panel, wxID_ANY, "0.00");
 	calsizer->Add(m_mag_field, 0, wxLEFT, 20);
-	text = new wxStaticText(this, wxID_ANY, "Accelerometer");
+	text = new wxStaticText(panel, wxID_ANY, "Accelerometer");
 	calsizer->Add(text, 0, wxTOP|wxBOTTOM, 4);
 	vsizer = new wxGridSizer(1, 0, 0);
 	calsizer->Add(vsizer, 1, wxLEFT, 20);
 	for (i=0; i < 3; i++) {
-		m_accel[i] = new wxStaticText(this, wxID_ANY, "0.000");
+		m_accel[i] = new wxStaticText(panel, wxID_ANY, "0.000");
 		vsizer->Add(m_accel[i], 1);
 	}
-	text = new wxStaticText(this, wxID_ANY, "Gyroscope");
+	text = new wxStaticText(panel, wxID_ANY, "Gyroscope");
 	calsizer->Add(text, 0, wxTOP|wxBOTTOM, 4);
 	vsizer = new wxGridSizer(1, 0, 0);
 	calsizer->Add(vsizer, 1, wxLEFT, 20);
 	for (i=0; i < 3; i++) {
-		m_gyro[i] = new wxStaticText(this, wxID_ANY, "0.000");
+		m_gyro[i] = new wxStaticText(panel, wxID_ANY, "0.000");
 		vsizer->Add(m_gyro[i], 1);
 	}
 
 	calsizer->AddSpacer(8);
-	text = new wxStaticText(this, wxID_ANY, "");
+	text = new wxStaticText(panel, wxID_ANY, "");
 	text->SetLabelMarkup("<small>Calibration should be performed\n<b>after</b> final installation.  Presence\nof magnets and ferrous metals\ncan alter magnetic calibration.\nMechanical stress during\nassembly can alter accelerometer\nand gyroscope calibration.</small>");
 	//text->Wrap(200);
 	//calsizer->Add(text, 0, wxEXPAND | wxALIGN_CENTER_HORIZONTAL, 0);
 	calsizer->Add(text, 0, wxALIGN_CENTER_HORIZONTAL, 0);
 
-	topsizer->SetSizeHints(this);
-	SetSizerAndFit(topsizer);
+	panel->SetSizer(topsizer);
+	topsizer->SetSizeHints(panel);
+	Fit();
 	Show(true);
 	Raise();
 
@@ -231,6 +237,7 @@ MyFrame::MyFrame(wxWindow *parent, wxWindowID id, const wxString &title,
 
 void MyFrame::OnTimer(wxTimerEvent &event)
 {
+	static int firstrun=1;
 	float gaps, variance, wobble, fiterror;
 	char buf[32];
 	int i, j;
@@ -238,6 +245,12 @@ void MyFrame::OnTimer(wxTimerEvent &event)
 	//printf("OnTimer\n");
 	if (port_is_open()) {
 		read_serial_data();
+		if (firstrun && m_canvas->IsShown()) {
+			//int h, w;
+			//m_canvas->GetSize(&w, &h);
+			//printf("Canvas initial size = %d, %d\n", w, h);
+			firstrun = 0;
+		}
 		m_canvas->Refresh();
 		gaps = quality_surface_gap_error();
 		variance = quality_magnitude_variance_error();
diff --git a/rawdata.c b/rawdata.c
index 0547248..e230036 100644
--- a/rawdata.c
+++ b/rawdata.c
@@ -25,7 +25,7 @@ static int choose_discard_magcal(void)
 	int32_t rawx, rawy, rawz;
 	int32_t dx, dy, dz;
 	float x, y, z;
-	uint64_t distsq, minsum=0xFFFFFFFFFFFFFFFF;
+	uint64_t distsq, minsum=0xFFFFFFFFFFFFFFFFull;
 	static int runcount=0;
 	int i, j, minindex=0;
 	Point_t point;
diff --git a/resource.rs b/resource.rc
similarity index 52%
rename from resource.rs
rename to resource.rc
index 6d3784b..ae193a5 100644
--- a/resource.rs
+++ b/resource.rc
@@ -1 +1,2 @@
 MotionCal ICON "icon.ico"
+#include "wx/msw/wx.rc"
diff --git a/serialdata.c b/serialdata.c
index 1c35dd8..0ece385 100644
--- a/serialdata.c
+++ b/serialdata.c
@@ -622,7 +622,7 @@ int write_serial_data(const void *ptr, int len)
 void close_port(void)
 {
 	CloseHandle(port_handle);
-	port_handle = NULL;
+	port_handle = INVALID_HANDLE_VALUE;
 }