Make the documentation clearer, match the documentation when no buttons are pressed for an event

components/lua_ui/widget.cpp

@@ -156,9 +156,11 @@ namespace LuaUi
         MyGUI::IntPoint absolutePosition = mWidget->getAbsolutePosition();
         osg::Vec2f offset = position - osg::Vec2f(absolutePosition.left, absolutePosition.top);
         sol::table table = makeTable();
+        int sdlButton = SDLUtil::myGuiMouseButtonToSdl(button);
         table["position"] = position;
         table["offset"] = offset;
-        table["button"] = SDLUtil::myGuiMouseButtonToSdl(button);
+        if (sdlButton == 0) // nil if no button was pressed
+            table["button"] = sdlButton;
         return table;
     }
 

files/lua_api/openmw/ui.lua

@@ -217,7 +217,8 @@
 -- @type MouseEvent
 -- @field openmw.util#Vector2 position Absolute position of the mouse cursor
 -- @field openmw.util#Vector2 offset Position of the mouse cursor relative to the widget
--- @field #number button Mouse button which triggered the event (could be nil)
+-- @field #number button Mouse button which triggered the event.
+--   Matches the arguments of @{openmw_input#input.isMouseButtonPressed} (`nil` for none, 1 for left, 3 for right).
 
 ---
 -- Register a new texture resource. Can be used to manually atlas UI textures.