On my machine with Window Maker the behaviour is slightly different: all Alt- shortcuts work, and Alt-Tab switching works, but swallows the first keypress in the new window. In xterm, the cursor changes from shallow to filled after the swallowed keypress, as if the window receives the keyboard focus only after a key is pressed in it; in GUI windows, text cursor only appears after the first (swallowed) keypress, too.
Is it somehow related to the "Grab updates to XKB data from XFree86 CVS" changelog item? Like "fix Meta, Super, Hyper keysyms interpretation"? -- Dmitry Borodaenko