Please, make sure that the sizes of your grid container (div test) applied successfully on your page.
Note, that the sizes in percents will be applied only if the parent container (or the html body) has defined sizes.
If the problem still occurs for you please, provide a complete demo or a demo link, where the problem can be reproduced locally.
The problem is with the initialization of the treegrid without the data.
In the 6.1 we have extended this scenarion and now you are able to initialize the grid without the data (so the cdn works correctly)