Disposed controls problem

Hello,

I have a problem with a .Net Compact Framework application.

My application contains several forms that are switched using show and hide
(the Show() and Hide() methods not ShowDialog() and Close()).

The problem occurs when I switch to other applications (like Word, Excel…)
and returns to my application. After switching to another form in my
application an ObjectDisposedException is thrown. It's not a constant problem
so it's hard to find it sometimes. I noticed that it occurs more when the
free memory is low but not always, once it happened when there was more than
30 Mb free (in the Application allocated storage). I read somewhere that the
Pocket PC OS closes application in the background when the user switches to
other application and there is not enough space to load them, but my problem
is that my application is not closed – only some Controls are disposed
sometimes. I can't predict or even check if the Control was disposed because
there isn't an IsDisposed property in Compact Framework.

My configuration:
Device: Pocket-PC i-mate
OS Ver.: 4.20.0


Thanks,
Sharon