Owner's silhouette rule: VTank's own controls are never shrunk/moved/
reordered to make room for MossTank extras. The Buffs tab's Difficulty "+"
button (338,108,26,20) overlapped the Extra Buff Spells "Add..." button
(336,102,120,16) because both VTank lists had been narrowed to 246/256x84
to coexist with MossTank's toggle/difficulty/rebuff/Buff-cast-now block in
the same two columns.
Fix: restore both lists to VTank's real 320x116 at the far left (x=4) and
far right (x=524) with their own 120-wide "Add..." row below each list.
Move the MossTank-only extras block (7 toggles, Difficulty +/-, Rebuff +/-,
the Buff button+status, Coverage) into the empty 184px middle strip between
the two lists that VTank's own layout never uses. Coverage moves to y=178
(194-16) per the upcoming bottom-fit rule.
Also fixed: a second real overlap the new pin found on the Options tab —
"Pet Min. Monsters:" (614,48,125,16) overlapped its own field
(734,48,40,16) by 5px; narrowed the label to the same 120px column width
every other label/field pair in that block uses.
Added AuthoredControlsInTheSameContainerNeverOverlapASibling (4 file cases)
plus a direct predicate pin (AssertNoSiblingOverlap_CatchesARealOverlap...)
proving the helper catches a real overlap, ignores touching edges, and
ignores two <group> tab-pages sharing one rectangle (mutually exclusive via
their own visible="{...}" binding) — the existing AssertWithinParent only
ever checked a child against its OWN parent's bounds, never against a
sibling.
Mutation check: setting DifficultyUp's button to (472,112) — the same rect
as DifficultyDown — turned AuthoredControlsInTheSameContainerNeverOverlapASibling
red against the real mosstank.xml ("<button> text='-' ... overlaps sibling
<button> text='+' ..."); reverting turns it green.
tests/AcDream.Plugins.MossTank.Tests: 665/665 (was 660/660, +5: the new
theory's 4 file cases + 1 predicate fact).
tests/AcDream.App.Tests --filter Markup|Plugin|UiMenu|Slider: 276/3 skipped/279 (unchanged).
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
0c2c3b572d