diff --git a/watchos2/Module_UI.cpp b/watchos2/Module_UI.cpp
index f7704dd..d87b3ff 100644
--- a/watchos2/Module_UI.cpp
+++ b/watchos2/Module_UI.cpp
@@ -12,6 +12,8 @@ struct UiWindow
 	byte layout_mode;
 	UiWindow* parent;
 	bool dirty;
+	bool needs_draw;
+	byte x, y, w, h;
 };
 
 struct UiFont
@@ -57,7 +59,6 @@ void Module_UI::start()
 	}
 
 	m_root = createWindow(WATCHOS_HANDLE_NULL);
-
 	module_power = static_cast<Module_Power*>(watchos::module(WATCHOS_MODULE_POWER));
 }
 
@@ -81,6 +82,7 @@ kernel_handle_t Module_UI::createWindow(IDrawable* drawable, kernel_handle_t par
 			m_window[i]->layout_mode = MODULE_UI_LAYOUT_MODE_NONE;
 			m_window[i]->parent = nullptr;
 			m_window[i]->dirty = true;
+			m_window[i]->needs_draw = false;
 
 			if (parent != WATCHOS_HANDLE_NULL)
 			{
@@ -162,12 +164,47 @@ void Module_UI::do_draw()
 		}
 	}
 
-	// TODO: Redraw only parts of the screen if necessary, etc
-	// Also confirm that anything was actually drawn. Could mitigate the risk of extraenous draw calls
-	// from multicore (see above comments in draw())
-	// false does a full invert/etc, true just updates in place and can leave ghosting/etc
-	// do false on a full-screen redraw, false otherwise? trigger a full-screen redraw every certain number of redraws?
-	gfx.display(!m_redraw);
+	// Actually figure out what to draw
+	bool whole_screen = false;
+	int x, y;
+	for (int i = 0; i < MODULE_UI_MAX_WINDOWS; i++)
+	{
+		if (m_window[i] != nullptr && m_window[i]->needs_draw)
+		{
+			get_screen_coordinates(m_window[i], &x, &y);
+			if (x == 0 && y == 0 && m_window[i]->w == DISPLAY_WIDTH && m_window[i]->h == DISPLAY_HEIGHT)
+			{
+				whole_screen = true;
+				break;
+			}
+		}
+	}
+
+	if (whole_screen)
+	{
+		for (int i = 0; i < MODULE_UI_MAX_WINDOWS; i++)
+		{
+			if (m_window[i] != nullptr)
+			{
+				m_window[i]->needs_draw = false;
+			}
+		}
+
+		gfx.display(!m_redraw);
+	}
+	else
+	{
+		for (int i = 0; i < MODULE_UI_MAX_WINDOWS; i++)
+		{
+			if (m_window[i] != nullptr && m_window[i]->needs_draw)
+			{
+				get_screen_coordinates(m_window[i], &x, &y);
+				gfx.displayWindow(x, y, m_window[i]->w, m_window[i]->h);
+				m_window[i]->needs_draw = false;
+			}
+		}
+	}
+
 	m_redraw = false;
 
 	module_power->enableDeepSleep();
@@ -181,11 +218,27 @@ void Module_UI::draw_window(UiWindow* window, int x, int y, int width, int heigh
 	m_draw_w = width;
 	m_draw_h = height;
 
+	// Track the last calculated position for this window so we can actually figure out
+	// where to update the screen.
+	if (window->parent != nullptr)
+	{
+		window->x = x - window->parent->x;
+		window->y = y - window->parent->y;
+	}
+	else
+	{
+		window->x = x;
+		window->y = y;
+	}
+	window->w = width;
+	window->h = height;
+
 	// Draw window
 	if (window->drawable != nullptr && (window->dirty || m_redraw))
 	{
 		window->drawable->draw(window->handle);
 		window->dirty = false;
+		window->needs_draw = true;
 	}
 
 	// Count children
@@ -238,7 +291,13 @@ void Module_UI::draw_window(UiWindow* window, int x, int y, int width, int heigh
 		}
 		break;
 	case MODULE_UI_LAYOUT_MODE_ABSOLUTE:
-			// TODO:
+		for (int i = 0; i < MODULE_UI_MAX_WINDOWS; i++)
+		{
+			if (m_window[i] != nullptr && m_window[i]->parent == window)
+			{
+				draw_window(m_window[i], x + m_window[i]->x, y + m_window[i]->y, m_window[i]->w, m_window[i]->h);
+			}
+		}
 		break;
 	}
 }
@@ -256,6 +315,23 @@ void Module_UI::setLayoutMode(kernel_handle_t window_handle, byte layout_mode)
 	watchos::panic("Trying to set layout mode on non-existent handle: %#010x", window_handle);
 }
 
+void Module_UI::setAbsolutePosition(kernel_handle_t window_handle, byte x, byte y, byte w, byte h)
+{
+	for (int i = 0; i < MODULE_UI_MAX_WINDOWS; i++)
+	{
+		if (m_window[i] != nullptr && m_window[i]->handle == window_handle)
+		{
+			m_window[i]->x = x;
+			m_window[i]->y = y;
+			m_window[i]->w = w;
+			m_window[i]->h = h;
+			return;
+		}
+	}
+
+	watchos::panic("Trying to set position on non-existent handle: %#010x", window_handle);
+}
+
 void Module_UI::setDirty(kernel_handle_t window_handle)
 {
 	for (int i = 0; i < MODULE_UI_MAX_WINDOWS; i++)
@@ -283,7 +359,7 @@ int Module_UI::getHeight()
 
 void Module_UI::fill(uint16_t colour)
 {
-	fill(m_draw_x, m_draw_y, m_draw_w, m_draw_h, colour);
+	fill(0, 0, m_draw_w, m_draw_h, colour);
 }
 
 void Module_UI::fill(int x, int y, int width, int height, uint16_t colour)
@@ -328,6 +404,18 @@ void Module_UI::local_to_screen(int* x, int* y)
 		*y = m_draw_y + *y;
 }
 
+void Module_UI::get_screen_coordinates(UiWindow* window, int* x, int* y)
+{
+	*x = window->x;
+	*y = window->y;
+	while (window->parent != nullptr)
+	{
+		window = window->parent;
+		*x = *x + window->x;
+		*y = *y + window->y;
+	}
+}
+
 void Module_UI::registerFont(byte id, const void* font)
 {
 	for (int i = 0; i < MODULE_UI_MAX_FONTS; i++)
diff --git a/watchos2/Module_UI.h b/watchos2/Module_UI.h
index 1619231..4e4c5c4 100644
--- a/watchos2/Module_UI.h
+++ b/watchos2/Module_UI.h
@@ -38,6 +38,7 @@ class Module_UI : public Task, public IRunnable
 
 	void draw_window(UiWindow* window, int x, int y, int width, int height);
 	void local_to_screen(int* x, int* y);
+	void get_screen_coordinates(UiWindow* window, int* x, int* y);
 
 public:
 	Module_UI();
@@ -53,6 +54,7 @@ public:
 	void do_draw();
 
 	void setLayoutMode(kernel_handle_t window_handle, byte layout_mode);
+	void setAbsolutePosition(kernel_handle_t window_handle, byte x, byte y, byte w, byte h);
 	void setDirty(kernel_handle_t window_handle);
 
 	int getWidth();