example: make available childs more discoverable
(I'm filing this for the example but all applications using HdyLeaflet have that issue although it's not HdyLeaflet's fault):
When moving to the header bar it's currently not possible to get back to the content that was displayed before switching to the sidebar. So while there's a back button there's no forward button.
Since this will affect several application using HdyLeaflet we might want to come up e.g. with a widget that can be put into the header bar for three pane apps that allows to select the differen panes. Alternatively we could establish gestures for that.