Playing around with the new controls and am wondering why the SplitContainer is fixed to 2 panels/1 split.  Wouldn't it make sense to allow the addition of a collection of panels that have splitters between them?  It may make resizing a little harder but not too much.

You can always add another SplitContainer in the panel of the first one to achieve that.

I think this two panel restriction is a cleaner design, because each SplitContainer can have a horizontal or vertical splitter, and you can design deeply nested splits this way, which would be hard to do if a SplitContainer had >2 panels.

+----------------------------------+
|                1        3        |
|                1        344444444|
|                1        3        |
|                1        3        |
|                122222222222222222|
|                1                 |
|                1                 |
|                1                 |
|                1                 |
|                1                 |
+----------------------------------+

(the numbers represent one splitter)

You can always add another SplitContainer in the panel of the first one to achieve that.

I think this two panel restriction is a cleaner design, because each SplitContainer can have a horizontal or vertical splitter, and you can design deeply nested splits this way, which would be hard to do if a SplitContainer had >2 panels.

+----------------------------------+
|                1        3        |
|                1        344444444|
|                1        3        |
|                1        3        |
|                122222222222222222|
|                1                 |
|                1                 |
|                1                 |
|                1                 |
|                1                 |
+----------------------------------+

(the numbers represent one splitter)

True this could be done, however what if you want 3 panels in the same direction and evenly split them.  You could do this with nesting a SplitContainer in a SplitContainer, but it wouldn't be as nice a solution.