diff --git a/xpra/x11/desktop/monitor_server.py b/xpra/x11/desktop/monitor_server.py
index 119edabb66..18ad97abc8 100644
--- a/xpra/x11/desktop/monitor_server.py
+++ b/xpra/x11/desktop/monitor_server.py
@@ -390,8 +390,8 @@ def _process_configure_monitor(self, proto, packet : PacketType) -> None:
             resolution = packet[2]
             if isinstance(resolution, str):
                 resolution = parse_resolution(resolution, self.refresh_rate)
-            assert isinstance(resolution, (tuple, list)) and len(resolution)==2
-            width, height = resolution
+            assert isinstance(resolution, (tuple, list)) and len(resolution) in (2, 3)
+            width, height = resolution[:2]
             self.add_monitor(width, height)
         else:
             raise ValueError(f"unsupported 'configure-monitor' action {action!r}")