Windows and Tabs API Extensions adds the following:
- Fixes a bug with BrowserTabGroupManager.create which destabilizes Opera (build 1387) if grouped tab is already part of a group. (The fix merely ungroups each tab before creating the new group)
- Defines a global TabUtils object with useful helper methods
- Adds nextSibling and previousSibling properties to BrowserTab and BrowserTabGroup objects. These let you get the adjacent tabs/groups in a tab or group's container.
- Adds nextTab and previousTab properties to BrowserTab objects. These let you get the tabs immediately to the left and right of a given tab.
- Adds firstTab and lastTab properties to BrowserTabGroup objects. These let you get the leftmost and rightmost tabs in a group.
- Adds an ungroup() method to BrowserTab objects, which (if possible) removes the tab from its group.
- Adds an at() method to BrowserTabGroup and BrowserWindow objects, which finds the tab or group at a given position.
- Adds an insertAfter() method to BrowserTabGroup and BrowserWindow objects, which acts just like insert(), but adds the item after the child item instead of before it.
- Adds a move() method to BrowserTabGroup and BrowserWindow objects, which moves a tab or group to a given position within the group or window.
You can find the library and more information about it on its Github page.