Thank you for the fix! Can you help me understand a bit better? Thanks!

@Piinks
TabBar and TabBarView interactions are quite complex (a lot of controllers and listeners involved). 😅

While trying to write a detailed explanation for this PR, I found an easier fix. I put the draft explanation, I started to write, at the end of this comment for future reference.

The issue happened only when switching from one tab to a non adjacent one (using PageController.jumpToPage on a non-adjacent page triggers scroll notifications and scroll activities that produces a listeners hell 😄 ). When TabController.animationDuration is not set to Duration.zero, existing code already dealt with this by treating separately adjacent and non adjacent moves. When TabController.animationDuration is set to Duration.zero, existing code jump to selected tab without taking care if it is an adjacent or non-adjacent tab.

So instead of fixing the consequences of jumping straight away to a non adjacent page (my previous fix), this new fix relies on the same solution used by existing code (jumping in two steps).

Draft explanation for future reference.

The TabBarView manages two controllers, a PageController and a TabController.
TabBars have a reference to the same TabController and also create a ScrollController (when TabBar.isScrollable is true).

TabController also owns an AnimationController. This AnimationController has several listeners :

• To animate the TabBar label, TabBar inserts a _TabStyle Widget which is an AnimatedContainer tied to the AnimationController owned by the TabController.
• _TabBarViewState listens to the AnimationController and updates the PageController accordingly.

When the user selects a new tab, _TabBarState_handleTap is called, the TabController selected index is updated (in _TabController_changeIndex) and the AnimationController owned by TabController is updated too. The PageController owned by TabBarView is also updated because it listens to the AnimationController.
Updating the PageController (jumpTo) emits a ScrollNotification.
_TabBarViewState listens to the PageController scroll notifications and calls TabController.index setter which calls again in _TabController_changeIndex and a new ScrollNotification is emitted. The issue was related to the second scroll notification triggering a new ScrollActivity that started a Ticker. When this Ticker ticks, a scroll notification is again emitted and TabController AnimationController is again updated.

Thank you for the detailed break down! Very thorough!