FIX. RadSplitContainer - InvalidCastException when calling the NextNavigationButton.PerformClick method
Unable to cast object of type 'System.EventArgs' to type 'System.Windows.Forms.MouseEventArgs'.
Workaround: use the SpliPanel.Collapsed property to control whether the split panel is expanded or collapsed.
The exception will no longer throw if you use version Telerik UI for WinForms R1 2017 (2017.1.117). However, calling the PerformClick method on the NextNavigationButton or the PrevNavigationButton won`t collapse or expand the split panel. This is a known issue which is already logged in our Feedback Portal. You can track its progress, subscribe for status changes and add your comment to it on the case page: https://feedback.telerik.com/Project/154/Feedback/Details/211163-add-radsplitcontainer-expose-api-for-accessing-the-splitter-buttons-and-perfor