[Lazarus] really strange messagedlg hang

[Luca Olivetti]

Hello,

I have a relatively complex, multithreaded application, compiled with 
lazarus 1.6.4/fpc 2.6.4 (it's the same application I reported in 
fpc-devel having a problem with tthread.synchronize but I cannot find in 
in the archive right now, the thread was "Suspicion about 
TThread.Synchronize").

The customer is in the process of migrating their PCs still running 
windows xp to windows 7 (yes, I know, I know...)

In this application, and this application only, upon the switch to 
windows 7, a call to MessageDlg hangs for a long time (around one 
minute) before returning. I saw that on my development machine but I 
didn't mind since on the target machine it ran fine (when it was running 
under windows xp that is).

It's not MessageDlg itself (in other applications migrated to windows 7 
and compiled with the same lazarus/fpc versions we don't see the 
problem), but some strange interaction with my application, alas I 
cannot find where the problem lies.

If I recompile it with lazarus 2.0.2[*]/fpc 3.2.beta (cannot use 3.0.2 
due to the above mentioned thread issue) the problem disappears.

Any idea?

[*] would somebody pleas take a look at this bug? The solution seems 
simple but I'm not sure it's correct.
https://bugs.freepascal.org/view.php?id=35646


Bye
-- 
Luca Olivetti
Wetron Automation Technology http://www.wetron.es/
Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007