Hi Michael Nikolai,
Thanks for using Syncfusion product.
We are sorry for inconvenience caused. We are unable to reproduce the issue. We have prepared a simple sample, demonstrating the working of the sample and the same can be downloaded from the following links.
Could you please replicate your issue in the above sample and send back to us with more information so that we could able to sort out the cause of this issue and provide you a better solution.
Please let me know if any other concerns.