@Mark-J Thanks, yes, cmds.dockControl works in 2017, but it has very limited docking areas, I think only far-left and far-right. Not even alongside Attribute editor, outside of that layout.
Ah, I see, I also always thought that staying with cmds should provide better support and easier upgrades from version to version, I never thought there’d be some breaking change there. But as it turned out using QT seems to be a better bet in the end.
What do you mean by next to? I’m guessing on the right, but not in the same stack as the attribute editor / channel box?
Ah thats why I switched to Workspace, I remember now, it was so we could dock into the channel box tabs and NOT to entire side of the whole application 
@bob.w yes, exactly that 
That’s how cmds.dockControl works in Maya 2017, while cmds.workspaceControl creates a properly dockable widget.
Yeah, ran into that same problem.
cmds.dockControl before 2017 and cmds.workspaceControl after.
Though if I remember correctly, workspaceControl was easier to use.
At least from the context of mGui, now that I think about I should probably do some examples of setting up dockables controls.