Re-parking project tabs in the browser

Working with multiple projects open at once.

When I tear off a project tab, I park it beside another browser window so I can drag bins into other projects. I can park it anywhere on the screen. Problem is I don't know how to "re-park" the tab once I move it away. I end up with a full browser window and can't put it back where it came from.
Anyone know how to do this?
thx

FC 5.1.4

Just drag it back to the same place you tore it off from until there is a black outline, then drop it - effectively redocking it.

Here's a demo

[s149.photobucket.com]

A HA !!
I didn't know about the "black line". Tried everything else.

thx a lot Jude.

Anytime DM