`BasedOn="{StaticResource SegmentToggle}"` resolves while the dictionary is being built, so a
forward reference fails at load with "Cannot find resource named 'SegmentToggle'". The style now
sits after SegmentToggle and SegmentLabel, where its base already exists.
Guard: ThemeResourceTests gains the ordering rule — within one dictionary, no StaticResource may
point at a key defined later in the same file. The existence check alone passed this, which is
exactly why the app died on launch while the tests were green.
Root cause of the unreliable test results this session: a stale `testhost` held ytLive.dll locked,
so builds silently kept the previous assembly (MSB3027 on copy). Killed it; the suite now rebuilds
and the two new facts actually run.
Two bugs from the creator's first look at the new controls.
1. CRASH — '{DependencyProperty.UnsetValue}' is not a valid value for property 'Fill'.
The token conversion deleted `YtSliderKnobHoverBrush` while two slider triggers still
referenced it. WPF does not fail that at build time: it substitutes UnsetValue and throws at
the next layout, inside `Ellipse.OnRender` — so the first slider touched (the new opacity one)
killed the app. The brush is back, as a glossier version of the rest state.
Guard: `ThemeResourceTests` scans every app XAML and proves each {StaticResource} key is
defined (theme/App resources or the same file). Proven by removing the key again — the test
names it.
2. PREVIEW DID NOTHING — the preview bar is its own XAML rendering (not the rasterized strip the
compositor overlays), and it was hard-wired white-on-transparent, so the drawer's controls had
nothing to move. Now:
- `SocialBarTextBrush` / `SocialBarBackgroundBrush` come from the same `SocialBarStyle` the
renderer bakes, so preview and output cannot disagree.
- the preview draws the plate (same colour + opacity) and the drop shadow.
- the drawer applies changes to the live config as you edit (`ApplyAppearancePreview`), and
Cancel restores the pre-edit snapshot — so the preview tracks the controls without
persisting anything until Save.
46 tests green (theme, socials, design tokens, layout store, real-MainWindow meter test).
gramps