Shade tiled frame

Hi all,

I'd like to write a function to shade a tiled frame taking into account
that the frame tabbar could have been hidden (mode = 'tiled-alt'). I
found out that set_shaded('set') won't work for tiled-alt frames, which
seems sensible to me. So before setting the shaded state I save the
frame mode, which I restore later when unshading the frame. The problem
is that some unshades are triggered automatically by the manager (?)
when the alternative frame is shaded and there is nothing left to be
shown. For example, let A and B be the two frames for my current
workspace: 1) I shade A so B is maximized. 2) Now I shade B and A is
forced to maximize, leaving the shaded state. I can't figure out a
simple way to intercept this automatic shaded->unshaded transition so
that I can restore the original frame mode as explained before. Could
you give me a clue? I'm new to ion and still getting my way through the
api.

Thank you in advance

Regards
-Carlos