The following code shows how to display all the hidden panels.
using DevExpress.XtraBars.Docking;
// ...
while(dockManager1.HiddenPanels.Count > 0) {
dockManager1.HiddenPanels[0].Visibility = DockVisibility.Visible;
}
Imports DevExpress.XtraBars.Docking
' ...
While DockManager1.HiddenPanels.Count > 0
DockManager1.HiddenPanels(0).Visibility = DockVisibility.Visible
End While