I have 5 dockpanes that I have made that I want to dock together (if more than one is visible), is this possible? I know you can dock with ESRI dockpanes - but what about your own dockpanes?
Also can you dock the first dockpane (that's made visible) to dock at the bottom of a MapPane? Not the whole of the bottom of the Pro application?
Have you tried to set docking attributes(dock="group" dockWith="esri_core_contentsDockPane") in config.daml file?
Enter your own dockpane id instead of esri_core_contentsDockPane.
More info here: