diff --git a/repos/ports/src/virtualbox5/frontend/console.cc b/repos/ports/src/virtualbox5/frontend/console.cc
index 9bfc7f54c6..5154a16953 100644
--- a/repos/ports/src/virtualbox5/frontend/console.cc
+++ b/repos/ports/src/virtualbox5/frontend/console.cc
@@ -167,7 +167,9 @@ void GenodeConsole::_handle_input()
 		auto curr_mouse_button_bits = [&] () {
 			return (_key_status[Input::BTN_LEFT]   ? MouseButtonState_LeftButton   : 0)
 			     | (_key_status[Input::BTN_RIGHT]  ? MouseButtonState_RightButton  : 0)
-			     | (_key_status[Input::BTN_MIDDLE] ? MouseButtonState_MiddleButton : 0);
+			     | (_key_status[Input::BTN_MIDDLE] ? MouseButtonState_MiddleButton : 0)
+			     | (_key_status[Input::BTN_SIDE]   ? MouseButtonState_XButton1     : 0)
+			     | (_key_status[Input::BTN_EXTRA]  ? MouseButtonState_XButton2     : 0);
 		};
 
 		unsigned const old_mouse_button_bits = curr_mouse_button_bits();
diff --git a/repos/ports/src/virtualbox5/frontend/console.h b/repos/ports/src/virtualbox5/frontend/console.h
index 2b37739566..2bceea9d11 100644
--- a/repos/ports/src/virtualbox5/frontend/console.h
+++ b/repos/ports/src/virtualbox5/frontend/console.h
@@ -132,13 +132,6 @@ class GenodeConsole : public Console {
 
 		bool _key_status[Input::KEY_MAX + 1];
 
-		static bool _mouse_button(Input::Keycode keycode)
-		{
-			return keycode == Input::BTN_LEFT
-			    || keycode == Input::BTN_RIGHT
-			    || keycode == Input::BTN_MIDDLE;
-		}
-
 		void _handle_input();
 		void _handle_mode_change();
 		void _handle_cb_rom_change();
diff --git a/repos/ports/src/virtualbox6/input_adapter.h b/repos/ports/src/virtualbox6/input_adapter.h
index e9e757238d..1411f7b205 100644
--- a/repos/ports/src/virtualbox6/input_adapter.h
+++ b/repos/ports/src/virtualbox6/input_adapter.h
@@ -42,7 +42,9 @@ struct Input_adapter
 		{
 			return keycode == Input::BTN_LEFT
 			    || keycode == Input::BTN_RIGHT
-			    || keycode == Input::BTN_MIDDLE;
+			    || keycode == Input::BTN_MIDDLE
+			    || keycode == Input::BTN_SIDE
+			    || keycode == Input::BTN_EXTRA;
 		}
 
 		void handle_input_event(Input::Event const &);
@@ -105,7 +107,9 @@ void Input_adapter::Mouse::handle_input_event(Input::Event const &ev)
 	auto curr_mouse_button_bits = [&] () {
 		return (_key_status[Input::BTN_LEFT]   ? MouseButtonState_LeftButton   : 0)
 		     | (_key_status[Input::BTN_RIGHT]  ? MouseButtonState_RightButton  : 0)
-		     | (_key_status[Input::BTN_MIDDLE] ? MouseButtonState_MiddleButton : 0);
+		     | (_key_status[Input::BTN_MIDDLE] ? MouseButtonState_MiddleButton : 0)
+		     | (_key_status[Input::BTN_SIDE]   ? MouseButtonState_XButton1     : 0)
+		     | (_key_status[Input::BTN_EXTRA]  ? MouseButtonState_XButton2     : 0);
 	};
 
 	unsigned const old_mouse_button_bits = curr_mouse_button_bits();