How to: detect why a Form "dissapears"?
I have a MDI application. 

a) In that application I open a large MDI Form (`X`) and an other small non-MDI (`Y`). 
Now, when Y is active, I can see both Forms (Y is smaller than X). 
When I move my cursor over the screen and both forms, nothing happens.

b) Now I will click on the bigger inactive form `X` and then 

c) switch back to `Y` (came back to situation "a");  
When I leave (with mouse cursor) now my small(Y) form's area, that Y form will "disappear", some like I'd clicked on the big form and activated it.

But first of all, I didn't click on X, neither the X caption is active, however the small Y form goes backward and is not visible anymore.

How to track the problem?

I set a breackpoint to both the `Y_Resize` and `Y_LostFocus` events, but I don't breack on it when the Y "dissapears" backward the X... (
How to: detect why a Form "dissapears"?
===

I have a MDI application. 

a) In that application I open a large MDI Form (`X`) and an other small non-MDI (`Y`). 
Now, when Y is active, I can see both Forms (Y is smaller than X). 
When I move my cursor over the screen and both forms, nothing happens.

b) Now I will click on the bigger inactive form `X` and then 

c) switch back to `Y` (came back to situation "a");  
When I leave (with mouse cursor) now my small(Y) form's area, that Y form will "disappear", some like I'd clicked on the big form and activated it.

But first of all, I didn't click on X, neither the X caption is active, however the small Y form goes backward and is not visible anymore.

How to track the problem?

I set a breackpoint to both the `Y_Resize` and `Y_LostFocus` events, but I don't breack on it when the Y "dissapears" backward the X... (