Allow pinning of a static child pane / terminal

[jonwooding]

It would be highly convenient to able to configure a pane to be static across all tabs.

I'm hoping for a feature such as being able to right click and "always keep pane visible" on a terminal window so that when moving through tabs a single pane stays present. It could be complicated to 'insert' that pane into an existing layout on demand, but a possible workaround would be to have it as a feature in the layout. For example:
"My Layout"
child0: window
child1: notebook, parent: child0
child2: hpaned, parent: child1
terminal3: terminal, parent: child2
terminal4: terminal, parent: child2
child3: hpaned, parent: child1
terminal3: terminal, parent: child3
child4: vpaned, parent: child3
terminal5: terminal, parent: child4
terminal6: terminal, parent: child4

In the above example "terminal 3" could have a document open in an editor, and switching tabs within child1 would keep terminal 3 open. A, perhaps easier, workaround would be to allow the user to attach a terminal pane to an existing view. For example a hotkey of Meta+T prompts: attach pane to: and that pane now will show the output/view of the pane attached... this might get complicated with setting terminal environment variables used for displaying things with specific widths etc.

I'd be happy to do the work to implement if someone with more experience can provide guidance on where to begin the implementation and what an acceptable solution might look like.

Example:

Tab1:

Tab2: