Feature request: merge windows

[vincemolnar]

I want to be able to easily merge windows. Right now, I have to select all the tabs, then drag them into the other window. I see two ways to improve this experience:

• Drag a whole window into another window (preferred)
• Have a "Select All Tabs" button in the window block

[vliggio]

Just select the windows (manually or search) and click the second icon on the bottome. That will merge the selected tabs into a new window.