Hi Ranju,
Thank you for using Syncfusion products.
Enter and Leave events for ComboBoxBarItem :Yes, You can access Enter and Leave events of ComboBoxBarItem using ComboBoxBarItem.ListBox as follows.
[C#]
this.comboBoxBarItem1.ListBox.Enter += new EventHandler(ListBox_Enter);
this.comboBoxBarItem1.ListBox.Leave += new EventHandler(ListBox_Leave);
You can also make the panel with comboBox to act as toolbar using CommandBar which is used to create and host toolbar.
Please refer Online documentation on CommandBar in the following link
http://www2.syncfusion.com/ug_61/toolswin/CommandBarsPackage.html Sample referencePlease refer the simple sample demonstrates the above said features.
http://websamples.syncfusion.com/samples/Tools.Windows/F71975/main.htmPlease let me know if this helps you.
Regards,
Jaya