ehm... my english fails again! :p
I'm not sure about what you want to say (apply a default action??), but I'll try to answer to your question, however:
During navigation I use to open many tabs (for various reasons, for example I visit forums that clear the memory of unvisited topics after few time from your last visit, so I try to open all pages I want to read all together in order to don't loose this reference), but sometimes this tab are too much and I need to move them in another window.
So it will be very useful if I could select the first tab and, with shift+click, click on the last tab and select all them with only two clicks (instead of, for example, 15 clicks!), and then with contaxtual menu, move the tabs on another window.
Besides, I think that "Move to another window" would be more confortable to use than "merge": i select a tab or more tabs, then right click and "Move to another window -> New Window" or for example "Move to anothe window -> Window N° 3", without need of previously open a new window, without need of placing the destination window under the souce window and without dialogs to avoid closing the main window.
And, last but not least, I think this way is much more intuitive.