question re default menu width (WinAPI, C++)

[Gorlash]

I have a C++ application (non-MFC)with a menu on the main dialog.
I define the menu in my resource file, and instantiate it via:

hMainMenu = LoadMenu(g_hinst, MAKEINTRESOURCE(IDM_MENUMAIN));
SetMenu(hwnd, hMainMenu);
update_menu_elements() ; // check/un-check each menu item

I've noticed that every menu/submenu in the application has a blank space on the right side of the menu, which is roughly 60 pixels wider than the longest string in the menu. Why is this occurring?? There isn't anywhere in the resouce-file definition, nor in this instantiation code, where I specify any dimensions for the menues, so this is clearly a default setting of some sort.

Is there some simple way that I can modify the menu default settings? (By "simple", I mean that it's not important enough to me, to make everything owner-drawn, and take over rendering every single menu item!!).