Splitter Vertical
 

Bug: UIBuilder does not allow the SplitterStyle Layout property to be set to Vertical either by double-clicking the property or manual entry.

Workaround: Inserting the property and value with Notepad works and UIBuilder displays the splitter correctly.

Splitters also seem kinda flaky about squishing a controlled page to a set minimum size. Takes several drags of the splitter to get it to squeeze out the last 20-30 pixels.