There's a problem when using a SlidingZone inside a Splitter Pane, if the height of the Splitter exceeds 10000. Our production page includes a RadDockLayout, and we dynamically size the Splitter to the height of the layout, but this simple example demonstrates the problem:
I already answered your support ticket on the subject. For convenience I will post my answer here as well.
This problem occurs because of the height of the splitter / slidingzone. By when the sliding pane is collapsed it is positioned out of the viewport with CSS rule top: -9999px, and since the sliding zone is higher than 9999px and its bottom part remains inside the viewport.
To avoid this issue you can use the following CSS:
Thanks for your quick reply! Perhaps I'm not understanding how to properly implement your suggestion, but I could not get it to work. I implemented as pasted below, but the menu doesn't appear at all. Should I be manually reproducing the stylesheet for the entire skin?