Layout issue

[John Hendrikx]

 From an earlier posting on this list, I came to understand that in 
JavaFX 8 it is no longer allowed to modify the children list in 
layoutChildren, and that such modifications may need to be moved to the 
computerPref* methods.

However, I get a different odd issue, and I'm wondering exactly what is 
allowed and what isn't when it comes to layout (any documentation on this?)

What's happening is the following:

I got a (subclass of) BorderPane, at the top I have a tab-like control 
(let's call it a FilterControl).  At the center I got a TreeView.

When the BorderPane gets laid out, I set up the content for both the 
TreeView and the FilterControl.  I do this in layoutChildren or in 
computerPref* of the BorderPane -- it makes no difference.  Setting up 
the content for the FilterControl involves changing its children list.  
The TreeView probably will do the same (adding/removing Cells as needed).

Now, I'm seeing layout issues.  The BorderPane for example is often 
putting the TreeView right on top of the FilterControl (stuff is 
transparent, so I can see it).  With other attempts, the FilterControl 
is not visible at all (zero height).  Forcing an update (by changing 
focus) usually clears up the issue and the FilterControl will take its 
rightful spot and force the TreeView to be a little less high.

I'm thinking this is somekind of issue with layout and that I'm 
approaching this wrong causing the layout problems.  However, I don't 
quite understand what I'm possibly doing wrong -- modifying the children 
of the Top node of the BorderPane during BorderPane's own 
computePref/layoutChildren call should be perfectly fine right?

Any help appreciated!

--John