.Net winform property says Visible but I can't see it

Question

I have a weird situation where I open a form from my application, hide it, and when I try to show it a second time, the Visible property says true, TopMost true also, location is correct, yet I can't see it.

Any ideas where and what to look at to work out what the problem is?

(Note: there may be issues with event handlers/delegate, but I'm not too sure where to start)

UPDATE - I set ShowInTaskbar to true - and I see it in the taskbar, but no way to bring it to front, and right click on the taskbar button does nothing. Alt-Tab neither. Doesn't show up in TaskManager.

Tried Crack.NET, but can't find any properties which let me get 'into' the object instance. .Net Memory Profiler doesn't help for this, I believe, and Winspector I'm not sure what to do with.

UPDATE2 - I lied, it's not directly a WinForm, I was inheriting from a custom class which in turn inherits from WinForm. I tried inheriting directly from Form and it works. So now I've got to go and look in the code of the custom class. I'll keep you posted...

Answer 1

Is the parent Window visible?

Windows has rules about children of non-visible windows being non-visible whatever their own visibility.

Answer 2

Could it be out of the screen boundaries? (that is, moved out).

Use Spy++ or Winspector and try to find this missing window and see exactly where/why it's hiding.

Answer 3

OK, nailed it.

The Custom form class has a 'cool' function - it fades in and out.

But only once, apparently.

So the reason I couldn't see the form is because the Opacity was 0!