Hi Kamen,
We can use the FixedPanel property of the SplitContainerAdv to keep one panel fixed so that the other panel will shrink/grow when the form is resized.
// To make panel1 shrink/grow during resizing
this.splitContainerAdv1.FixedPanel = Syncfusion.Windows.Forms.Tools.Enums.FixedPanel.Panel2;
I have attached a sample that illustrates the same. Please have a look at it and let me know if this meets your requirement.
Thanks for your interest in Syncfusion products.
http://websamples.syncfusion.com/samples/tools.Windows/F59983/main.htmBest regards,
Golda