What steps are necessary to merge two windows with a lot of tabs in each

[Claire]

I'd like all the tabs in one window to be merged and show in another window.

When I drag the window and place it as a child of another window the window tabs are not merged there are still 2 windows.
If I try to delete just the window subnode all the tabs get deleted, same with close.
There are a lot of tabs and no way I could find to select multiple items unless they are all under a parent for drag and drop.

Any suggestions?

In tab outliner I could just drag the window into another window in the list and the tabs would move to that window

Thanks

[Claire]

this can be done in chrome by selecting 1st tab by clicking on it then shift clicking on the last tab you want to move. then dragging the selected tabs to a different window.