How to navigate in Winforms Designer?

I'm not understanding how to navigate amongst components of a UserControl in the Winforms Designer. Let me illustrate.

Suppose I have a UserControl that has several layers, say a SplitContainer, Dock=Fill, with controls in each of the split panels, also Dock=Fill. Now only the controls filling the SplitContainer panes are visible. I can select either of them and see their property sheets. But how do I select the controls behind them that are not visible? For example, how would I select the base UserControl?

In Visual Studio, there's a drop-down at the top of the property sheet that lets you select from any of the components in the control. I'm looking for equivalent functionality in the Rider Designer.

TIA!