Dragging tabs between windows causes display issues/unresponsiveness

[devonparsons]

Short description

In Firefox Quantum, dragging a tab (or tab tree) from one WINDOW to another causes errant behavior (invisible tabs, frozen window)

Steps to reproduce

1. Start Firefox with clean profile.
2. Install TST.
3. Open a number of tabs in a tree in one window.
4. Open a new window
5. Drag a tab tree to the new window

Expected result

The tabs I dragged to the new window appear in the Tree
The window I dragged the tabs FROM is responsive

Actual result

The tabs I dragged to the new window are not visible. Because I hide the top bar using userChrome, the only way to access those tabs is to hit ctrl + pageup and ctrl + pagedn. The tabs are clearly attached to the window, but they are not displayed in the tree. No tab appears selected.

The window I dragged the tabs FROM is unresponsive. I seem to need to click around/minimize the program/alt tab a few times before it will respond.

Environment

• Platform (OS): Windows 10
• Version of Firefox: Quantum (57)
• Version (or revision) of Tree Style Tab: Latest (All this was done on a brand new computer yesterday)

userChrome.css, in case it is interfering:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
/*
  * TreeStyleTabs solutions to remove tabs
  *
  * Solution by: https://news.ycombinator.com/item?id=15343940 */
#TabsToolbar, #sidebar-header {
  visibility: collapse !important;
}

#TabsToolbar {
  margin-bottom: -21px !important;
}

[devonparsons]

Sorry, to clarify: The window remains responsive during that time, it's only TST that is unresponsive. And I just noticed a small dot that probably indicates that it's loading something. But the timeframe for loading is quite long (~ 7seconds)

[devonparsons]

Screenshot: A window with apparently no tabs attached, but clearly pointed at github

[piroor]

Sorry, there is a regression around this operation. Recent commit should fix this...

[kiersch]

The issue persists under Ubuntu MATE 17.10

[caudate-julie]

Same issue today, Windows 10
Though the source window tree is only irresponsible for about 10 seconds.
Also if I close the destination window and open ot again (from recent closed), all invisible tabs appear in the tree.