In Visual Studio there seem to be two types of groups of panes:
1. one set that are inside a permanent panel set unchangeably to Group, and
2. one outer set that behave pretty much like netadvantage DockManager set to LayeredWindowWithIndicators.
How can I get that inner group behavior?
I can drag-split the contents of this permanent area into two or more areas. (05_visualstudio_dragpane_inner.png)
I can even mix files and panes, and they all have a tag on the top. (04_visualstudio_pane_with_files.png)
And if I drag a pane into this area, I can drop it into it. (03_visualstudio_dragpane_in.png)
Because if I open files, they open inside this area. (02_visualstudio_withfiles.png)
OK, here comes the full explanation :)
This is what Visual Studio looks like. Note the docked panes surround an empty area.
This area is not just empty, it is a "permanent" area. (01_visualstudio_permanant_area.png)