use-appsidepane-api
Use Xrm.App.sidePanes.createPane instead of Xrm.Panels.loadPanel.
Recommendation
The Xrm.Panels.loadPanel API is being replaced with Xrm.App.sidePanes.createPane because the former only supports a single pane while the latter supports multiple panes. For more information, go to Use with Xrm.App.panels.loadPanel.