resize notifications are broken

[MajorBreakfast]

My <paper-tabs> element draws it's selection bar incorrectly if I use it as a descendant of a <neon-animated-pages> element on an initially hidden page.

The culprit is this line. It's an optimization, but it's broken and I can't figure out what goes wrong. Can you remove it? (Or even better - fix it :)

[MajorBreakfast]

Got it! Did some codebase digging.
The current approach assumes that all children implement IronResizableBehavior which can then in turn forward the resize notification deeper down the tree.

• Either let NeonAnimatableBehavior inherit from IronResizableBehavior. Thus the behavior is always there and notifications can always be forwarded.
• Or forward the notification to descendants of the selectedPage element as well, not just the element itself.

The former has the advantage that it avoids tree walking as it doesn't require a descendancy check. The latter has the advantage that it doesn't complicate NeonAnimatableBehavior's inheritance chain. I'm not sure which one's better! What do you think?

I hope that this can be resolved. The need to manually implement the IronResizableBehavior if descendants need it is bad for usability. The element should just do "the right thing".

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Additional problem: _notifyPageResize() is called too late because it's only called after the animation has played. In my case the selection bar only appears after the animation has finished which leads to a flicker.
Edit: Submitted PR #116

[cdata]

Thanks for the suggestion and the contribution. I will take a look!

[MajorBreakfast]

@cdata Thanks for the quick response! I found some old open issues with the term "resize" from June. So, I was a bit worried :) Could you add the bug label as well? (My users won't know which tab is selected => bug)

• My PR only fixes that the selected page gets its resize notification earlier. The old page should probably still receive notifications until it becomes really invisible. That was previously the case.
• Also, a possible optimization would be to just notify a page if and only if <neon-animated-pages> received at least one notification itself while the page in question has been hidden. That requires some bookkeeping though. However, cloud be done by counting notifications for all invisible pages in a WeakMap. (undefined or >=1 would mean the newly selected page needs to be notified)

What do you think?

[cdata]

Sorry, I misread. You are correct that this is a bug. I think the implementation is just weird and needs to be fixed. I believe there is another issue open that talked about a similar problem.