Is there any? If not, what do you suggest? Right now we are using a plethora of split containers, and the way it’s coded makes it very difficult to add new controls, especially in the same panels, resizing is hopeless amongst other things. It could be recoded again using split containers in a much better way, but is there a better alternative?

Image courtesy of Sun’s “A Visual Guide to Layout Managers“.
It sounds like you want a
DockPanel.Here’s the demonstration image:
(source: microsoft.com)
which bears striking similarity to yours.
In WinForms, you just use the pre-existing
Dockproperty (see alsoAnchor), as described here: http://www.techrepublic.com/article/manage-winform-controls-using-the-anchor-and-dock-properties/6165908