Pinned tabs and "close all to the right / left"?

[Mister L]

Another request, depending how simple it would be...

Could it be possible to have pinned tabs? So that when we "close other tabs" they stay open along with the active tab?

Use cases:
- keep the css open when closing html files you're done working on;
- keep a "model" html file open to use when modifying other files so you can easily switch back and forth;
- no doubt others that I'll think of later.

It could also be useful to have the choice to close only the tabs to left or right of the active one (such as, all the ones you're done with, but not the ones you still need to work on), the way Notepad ++ does.

If it's too complicated no worries, just asking.