Update gtk widgets from within an effect plugin.

Hello,
currently I am writing an effect plugin. Now I've been trying to add a VU
meter (basically a bar showing the curerent signal level). 
in my crunching function I'm computing a maximum level, and tried to update
a gtk progress bar at most every 100 milliseconds. Unfortunalely, gtk freezes
sometimes alkso xmms hangs. After some poking and testing I discovered,
that no matter what user interface updates I trigger, xmms will hang very soon.

Is there a known problem with updating gtk display from within an audio plugin?

Does anyone have an example at hand of an effect plugin doing display updates?

TIA.
Timo.

P.S.:
I did not provide the source code, because it is not very intuitively usable. It is basically
an energizer consisting of an input leveller, a fourband multiband-compressor with
optional tube-saturation, and an output limiter, including a exciter.
As all parameters currently must be setup manually and no preset logic has
been implemented, only the very curious should try to use it. However, I can provide
the source code, if desired.

-- 

Mit freundlichen Grüßen / best regards

Timo Weggen

Loewe Opta GmbH
Kompetenzzentrum Hannover
Hildesheimer Str. 140
D-30173 Hannover
Telefon ++49 511 563549-46
Telefax ++49 511 563549-65
e-mail: [email protected]