add a hotkey to hide the UI widgets

OpenRA.Game/Settings.cs

@@ -181,6 +181,7 @@ namespace OpenRA
 		public Hotkey TogglePixelDoubleKey = new Hotkey(Keycode.PERIOD, Modifiers.None);
 
 		public Hotkey DevReloadChromeKey = new Hotkey(Keycode.C, Modifiers.Ctrl | Modifiers.Shift);
+		public Hotkey HideUserInterfaceKey = new Hotkey(Keycode.H, Modifiers.Ctrl | Modifiers.Shift);
 		public Hotkey TakeScreenshotKey = new Hotkey(Keycode.P, Modifiers.Ctrl);
 
 		public Hotkey Production01Key = new Hotkey(Keycode.F1, Modifiers.None);

OpenRA.Game/Widgets/RootWidget.cs

@@ -31,6 +31,14 @@ namespace OpenRA.Widgets
 					return true;
 				}
 
+				if (hk == Game.Settings.Keys.HideUserInterfaceKey)
+				{
+					foreach (var child in this.Children)
+						child.Visible ^= true;
+
+					return true;
+				}
+
 				if (hk == Game.Settings.Keys.TakeScreenshotKey)
 				{
 					if (e.Event == KeyInputEvent.Down)

OpenRA.Mods.Common/Widgets/Logic/SettingsLogic.cs

@@ -466,6 +466,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				var hotkeys = new Dictionary<string, string>()
 				{
 					{ "DevReloadChromeKey", "Reload Chrome" },
+					{ "HideUserInterfaceKey", "Hide UI" },
 					{ "TakeScreenshotKey", "Take screenshot" }
 				};