diff -r 039b3f8a3442 -r b498160cc2ab src/X11Command.h
--- a/src/X11Command.h	Mon Apr 05 15:37:28 2021 +0200
+++ b/src/X11Command.h	Mon Apr 05 18:09:25 2021 +0200
@@ -125,19 +125,17 @@
 		int proximityOut = UNUSED;
 	} eventType;
 
-	void registerEvents(const Display& display, const XDeviceInfo* deviceInfo) {
+	void registerEvents(const Display& display, int screen, const XDeviceInfo* deviceInfo) {
 		bool registerProximityEvents = false; // TODO: proximity?
 
 		Device device;
 		Window window;
-		int screen;
 
 		int eventCount = 0;
 		XEventClass events[7]; // TODO: check array size
 		XInputClassInfo* classInfo;
 		int classIndex;
 
-		screen = DefaultScreen(display.display);
 		window = RootWindow(display.display, screen);
 		// TODO: configurable window from which we capture the events or optionally open our own window (can also provide some visual feedback/info)
 		// Currently we can do something like:
@@ -198,7 +196,8 @@
 			devices.items = XListInputDevices(display.display, &devices.size);
 			for (int i = 0; i < devices.size; i++) {
 				if (devices[i]->type) {
-					registerEvents(display, devices[i]);
+					for (int screenCount = XScreenCount(display.display), screen = 0; screen < screenCount; screen++)
+						registerEvents(display, screen, devices[i]);
 				}
 			}
 		}
@@ -297,8 +296,7 @@
 		}
 
 		writer->writeAttribute(std::to_wstring(window));
-		// writer->writeAttribute(std::to_wstring(screen?));
-		// writer->writeAttribute(std::to_wstring(root_win));
+		writer->writeAttribute(std::to_wstring(windowAttributes.root));
 		writer->writeAttribute(std::to_wstring(parentWindow));
 		writer->writeAttribute(&level, typeid (level));
 		writer->writeAttribute(fetchWindowName(display, window));
@@ -317,8 +315,7 @@
 	void listWindows(const Display& display, Configuration& configuration, std::shared_ptr<writer::RelationalWriter> writer, std::function<void() > relationalWriterFlush) {
 		writer->startRelation(L"x11_window",{
 			{L"id", relpipe::writer::TypeId::INTEGER},
-			// {L"screen", relpipe::writer::TypeId::INTEGER},
-			// {L"root", relpipe::writer::TypeId::INTEGER},
+			{L"root", relpipe::writer::TypeId::INTEGER},
 			{L"parent", relpipe::writer::TypeId::INTEGER},
 			{L"level", relpipe::writer::TypeId::INTEGER},
 			{L"name", relpipe::writer::TypeId::STRING},
@@ -330,10 +327,36 @@
 			{L"height", relpipe::writer::TypeId::INTEGER},
 		}, true);
 
-		int screen = DefaultScreen(display.display);
-		Window window = RootWindow(display.display, screen);
+		for (int screenCount = XScreenCount(display.display), screen = 0; screen < screenCount; screen++) {
+			Window root = RootWindow(display.display, screen);
+			listWindow(display, root, 0, configuration, writer, relationalWriterFlush);
+		}
+	}
 
-		listWindow(display, window, 0, configuration, writer, relationalWriterFlush);
+	void listScreens(const Display& display, Configuration& configuration, std::shared_ptr<writer::RelationalWriter> writer, std::function<void() > relationalWriterFlush) {
+		writer->startRelation(L"x11_screen",{
+			{L"id", relpipe::writer::TypeId::INTEGER},
+			{L"root", relpipe::writer::TypeId::INTEGER},
+			{L"width", relpipe::writer::TypeId::INTEGER},
+			{L"height", relpipe::writer::TypeId::INTEGER},
+			// {L"width_mm", relpipe::writer::TypeId::INTEGER},
+			// {L"height_mm", relpipe::writer::TypeId::INTEGER},
+		}, true);
+
+		for (int screenCount = XScreenCount(display.display), screen = 0; screen < screenCount; screen++) {
+			Window root = RootWindow(display.display, screen);
+			XWindowAttributes attributes;
+			if (!XGetWindowAttributes(display.display, root, &attributes))
+				throw std::invalid_argument("Unable to get attributes for window: " + std::to_string(root));
+
+			writer->writeAttribute(std::to_wstring(screen));
+			writer->writeAttribute(std::to_wstring(root));
+			writer->writeAttribute(std::to_wstring(attributes.width));
+			writer->writeAttribute(std::to_wstring(attributes.height));
+			// writer->writeAttribute(std::to_wstring(attributes.screen->mwidth));
+			// writer->writeAttribute(std::to_wstring(attributes.screen->mheight));
+		}
+
 	}
 
 	static int handleXError(::Display* display, XErrorEvent* errorEvent) {
@@ -362,7 +385,7 @@
 			if (configuration.listInputDevices) listInputDevices(display, configuration, writer, relationalWriterFlush);
 			if (configuration.listInputEvents) listInputEvents(display, configuration, writer, relationalWriterFlush);
 			if (configuration.listWindows) listWindows(display, configuration, writer, relationalWriterFlush);
-			// TODO: list screens
+			if (configuration.listScreens) listScreens(display, configuration, writer, relationalWriterFlush);
 		} else {
 			throw std::invalid_argument("Unable to open display. Please check the $DISPLAY variable.");
 		}