Hi Otomar,
Thanks for using Syncfusion Products.
We would like to let you know that currently there
is no support to set the initial position of splitter in Gantt control. We have
consider this as feature request and it will be implemented in any of our
upcoming main release. We will update you once this feature has got
implemented.
Please let us know if you require further assistance
on this.
Regards,
John. R