You can send a simplified, but runnable project, or create a jsFiddle/jsBin demo.
Before that, you can try the following.
By default, the TreeView's outermost element (which has a .k-treeview CSS class) has an overflow:auto style applied. If you won't be needing TreeView scrolling, you can override this style:
This should prevent the issue, although the exact cause will remain unknown.
DevCraft Q1'14 is here! Join the free online conference to see how this release solves your top-5 .NET challenges. Reserve your seat now!