[xmonad] Problem with manage hook

[Maurício]

Hi,

I use this manageHook:

 mh = ( ask >>= doF . sink )

It works well except for a single application
('netgen', which uses a widget set that I can't
identify). When it opens a dialog window,
everything starts to flash (like if black and
white lights were alternating fast).

My wild guess is that when my manageHook
changes a widget parameter (size?) the widget
reacts changing it back, and I get an infinite
loop.

Do you think I could improve my manageHook
to solve that?

Thanks for your comments,
Maurício