Dialogs get hidden after window switch on win32

["alfred alfred" <alfred gtk gmail com>]

I am using gtk to write a multi-platform application. in my application, there is a big main window, and then several small modeless dialogs showing some extra information for the main window. but on win32, if I switch the main window off, and then switch it on, those small dialogs will disappear, and I can not find them except checking those windows one by one(I set Skip-taskbar to Yes for those dialogs). But it is okey on Linux.

Can anybody tell me how to do this problem?

Thanks.