Thank you for reporting the problem.
I have logged an issue in our official Github repository. Here is a link
to the issue, where you can track our progress on resolving it.
As a workaround of the problem you can use the calc()
function to calculate the height of the Dialog in persentage.
Note, that the pixels in the clac() function should be equal to the Dialog header and footer total height, including borders that are inside. The header and footer height are depending on the theme you are using. Here is a Dojo
example where the workaround is demonstrated.
As a sign of gratitude your Telerik points are now updated.