I would like to display a small window in my application, so that the user
can still see the full window in the background, the one that call my small
window to enter a value for some calculation.
Once the user enters the value in the small window, this one will disappear
and display the original full window that called the small one, very similar
to a MessageBox, that displays in a small window.

Can I do this??

Probably easiest to use create a Panel that you show/hide as appropriate.

Tx!
A litle bit more of work but oh well.....the app. looks better then.

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appropriate.

Yes, check out http://smartdevice.microsoftdev.com/Learn/Articles/637.aspx
(scroll down to figure 6) for an example. The source can be found at
http://www.windowsforms.net/taskvision.

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