Thanks for using Syncfusion product.
We have checked your query "How to set different height for each taskbar items in XPTaskBar". We have prepared sample based on your requirement in which we have set the height of XPTaskBar items by setting PADY property of XPTaskBarBox which was added as the item in XPTaskBar. Similarly, if you are using many XPTaskBar in your sample, by using the Size property of XPTaskBar you can set different height for each task bar. Please download the same from the below location.
If we misunderstood your requirement, please provide more information regarding the requirement and also conform us whether you are using XPTaskBar control in your sample. This would help us to proceed further.