Merging/Combining panels into one panel

I just want to see if there is a way to merge panels into one panel?
I see there is a button to split panels but I don’t see any button merging them. Any ideas?

There’s no way to merge panels but you can merge layers by selecting them and
going into menu-Layers-Merge Selected Layers.

For merging panels you could perhaps copy the layers you need from one panel
to the next and just delete the extra one.