2026-08-17 fixed the four Discover tabs, which were all instantiated
because `visible: false` hides an item without stopping QML from
building it. This is the same disease one level down and it is what was
left: a Repeater builds EVERY delegate in its model, so a ten-section
tab built ten rails, each rail's horizontal ListView then created its
own delegates during the first layout pass, and the viewport has room
for about two and a half.
That work is what `to-idle` was made of — the rails nobody could see
paying for their cards before the GUI thread could reach the event loop
and let a frame out.
The seed is one viewport and the rest arrive after the first frame. A
rail is ~328px with the Column spacing against a ~740px pane, so three
covers the fold; +2 per tick reaches even the twelve-section For You tab
inside ~80 ms. The `active &&` on the visibility gate is load-bearing:
a Column skips invisible children entirely, but an active:false Loader
is visible and 0px tall, which would reserve a spacing slot per pending
rail and collapse it as the rail lands.
Honest limit: this did NOT turn out to be what fills the blank stretch
between the acknowledgement frame and the content. Library has no such
ramp and shows the same shape, so that hypothesis is refuted and the
remainder is unattributed.
cc
vicrodh
dc8cb1fa32