VSync joins the video options, the chat dock goes quiet

- VSync is a player setting on the Graphics page now — 1.12's own gxVSync, persisted like every other CVar — instead of a dev-HUD checkbox
- the perf HUD collapses to one surface that says everything once, at a deliberate, governed width; the badge stops crying wolf
- the idle chat dock stops repainting itself every frame — the fade applier gets the gate the reference carries twice over, and hovering still reveals the hidden tabs
- the tick can name who spent it: per-handler self/total attribution at the one seam where every handler fires

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/benilla-app/src/ui_script/chat_tests.rs

@@ -648,3 +648,71 @@ fn fcf_select_dock_frame_selects_by_frame_and_raises_for_an_undocked_one() {
         "an undocked window raises — benilla has no dock model for it (0288 §2)"
     );
 }
+
+/// **The idle dock writes nothing** (decision 1396). `FCF_OnUpdate`'s apply block used to run
+/// unconditionally — ~24 `getglobal`s, two table builds and ~20 `SetAlpha` calls every frame of
+/// every session, writing the values that were already there, at 36 µs/frame (1395 measured it as
+/// the largest single handler in the client).
+///
+/// The probe is a sentinel the applier can never write: it only ever writes `{0, 0.5, 1.0} × reveal`,
+/// and `reveal` is pinned at 0 with the cursor away from the dock. If the gate is removed, the very
+/// next tick overwrites 0.42 with 0 and this goes red.
+#[test]
+fn an_idle_dock_stops_rewriting_the_tab_alpha_every_frame() {
+    let mut s = chat_frame();
+    s.mouse_move(1500.0, 850.0); // far from the dock: no hover, so `reveal` stays 0
+    for _ in 0..8 {
+        s.tick(0.016); // let the label measurements land and the applier reach its resting write
+        s.resolve();
+    }
+
+    s.run("ChatFrame1Tab:SetAlpha(0.42)").unwrap();
+    for _ in 0..10 {
+        s.tick(0.016);
+        s.resolve();
+    }
+    assert!(s.errors().is_empty(), "{:?}", s.errors());
+
+    let alpha: f64 = s.eval("return ChatFrame1Tab:GetAlpha()").unwrap();
+    assert!(
+        (alpha - 0.42).abs() < 1e-6,
+        "a settled dock must not rewrite its tab alpha — got {alpha}"
+    );
+}
+
+/// The control for the guard above: the gate must not cost the reveal it is gating. A stationary
+/// cursor over the dock for longer than `CHAT_TAB_SHOW_DELAY` fades the selected tab to full.
+#[test]
+fn hovering_the_dock_still_reveals_the_tabs() {
+    let mut s = chat_frame();
+    s.mouse_move(1500.0, 850.0);
+    for _ in 0..4 {
+        s.tick(0.016);
+        s.resolve();
+    }
+    assert!(
+        s.eval::<f64>("return ChatFrame1Tab:GetAlpha()").unwrap() < 1e-6,
+        "the dock starts concealed"
+    );
+
+    // The dock's own centre, asked of the layout rather than hardcoded.
+    let (x, y): (f32, f32) = s
+        .eval(
+            "return (ChatFrame1:GetLeft() + ChatFrame1:GetRight()) / 2, \
+             (ChatFrame1:GetBottom() + ChatFrame1:GetTop()) / 2",
+        )
+        .unwrap();
+    s.mouse_move(x, y);
+    // 0.2 s stationary to arm the reveal, then the 0.15 s ramp — 25 frames covers both with room.
+    for _ in 0..25 {
+        s.tick(0.016);
+        s.resolve();
+    }
+    assert!(s.errors().is_empty(), "{:?}", s.errors());
+
+    let alpha: f64 = s.eval("return ChatFrame1Tab:GetAlpha()").unwrap();
+    assert!(
+        (alpha - 1.0).abs() < 1e-6,
+        "a stationary hover reveals the selected tab at full alpha — got {alpha}"
+    );
+}

crates/benilla-app/src/ui_script/mod.rs

@@ -218,6 +218,17 @@ impl Default for UiScaleCvar {
 
 /// The shipped default (the reference's slider spans 0.64..1.0; 1.0 read oversized to the
 /// director's eye — the taste call this dial exists for).
+///
+/// **It also happens to be what the reference itself lands on above ~853 px tall**, which we did
+/// not know when it was chosen (wow-re `system/ui/scratch/modelframe-uiscale-law.md`, out of the
+/// autocast-shine thread): `0x492f70` computes `max((H > 768) ? 768/H : 1.0, 0.9)` and is called
+/// **both** on a mode set and from the `useUiScale`-OFF leg (`0x4908ad`) — and OFF is the shipped
+/// default (`0x8430c0` = `"0"`). So the reference is 1.0 at 768 and below, 0.96 at 1280×800, and
+/// **0.9 at 1080p and 1440p**. Our flat 0.9 therefore agrees with it on every modern window and
+/// diverges only *below* ~853 px tall, where the reference is nearer 1.0. Left alone deliberately:
+/// this constant is a director taste call, and the divergence is confined to window heights we
+/// do not ship against. The reference's own law is written here so the next session inherits it
+/// rather than re-deriving it.
 pub(crate) const DEFAULT_UI_SCALE: f32 = 0.9;
 
 /// The app's `uiScale`: `WOW_UI_SCALE=` if set (clamped to the plausible dial range), else

crates/benilla-app/src/ui_script/options_tests.rs

@@ -822,6 +822,56 @@ fn the_graphics_page_reads_the_cvar_table_on_select() {
     assert!(s.errors().is_empty(), "script errors: {:?}", s.errors());
 }
 
+/// **Vertical Sync** (1394) — the Graphics page's third row, and the first option in this window
+/// that reaches the *window* rather than a gameplay or UI knob. It is 1.12's own Video Options
+/// checkbox 5 (`gxVSync`), which lived on the perf HUD as a dev checkbox until it turned out to be
+/// unreachable in a player build (the HUD is `#[cfg(feature = "dev")]`) and to be a setting rather
+/// than an instrument in the first place.
+///
+/// The row is deliberately **not** deferred, unlike the UI Scale slider above it: the reference's
+/// row carries `gxRestart = 1` because its device could not swap the presentation interval live,
+/// and wgpu can — so the click commits, like every other checkbox here.
+#[test]
+fn the_vertical_sync_row_reads_and_writes_the_present_mode_cvar() {
+    let mut s = audio_harness();
+    s.set_cvar_host("gxVSync", "0");
+    let mut s = harness_on(s);
+    s.run("ShowUIPanel(OptionsFrame)").unwrap();
+    s.run("OptionsFrameCategoryListRowGraphics:Click()")
+        .unwrap();
+
+    // Read from the table, not from a restated default: the harness seeded it off.
+    assert!(!s
+        .eval::<bool>("return OptionsFrameContainerBodyGraphicsRowVerticalSyncCheck:GetChecked()")
+        .unwrap());
+    assert_eq!(
+        s.eval::<String>("return OptionsFrameContainerBodyGraphicsRowVerticalSyncLabel:GetText()")
+            .unwrap(),
+        "Vertical Sync"
+    );
+    let _ = s.take_cvar_changes();
+
+    // A click commits immediately — nothing stages it behind Apply.
+    s.run("OptionsFrameContainerBodyGraphicsRowVerticalSyncCheck:Click()")
+        .unwrap();
+    assert_eq!(
+        s.take_cvar_changes(),
+        vec![("gxVSync".to_string(), "1".to_string())],
+        "the checkbox writes the cvar on click, not on Apply"
+    );
+
+    // Defaults walks it back to the registered "1" — which `cvars::tests` welds to
+    // `VideoConfig::default()`, and `video::tests` welds in turn to the window's boot mode.
+    s.run("OptionsFrameContainerBodyGraphicsRowVerticalSyncCheck:Click()")
+        .unwrap();
+    let _ = s.take_cvar_changes();
+    s.run("OptionsFrameContainerDefaults:Click()").unwrap();
+    assert!(s
+        .eval::<bool>("return OptionsFrameContainerBodyGraphicsRowVerticalSyncCheck:GetChecked()")
+        .unwrap());
+    assert!(s.errors().is_empty(), "script errors: {:?}", s.errors());
+}
+
 /// The dropdown row (0992, the first): the capsule reads the CVar on select (text from the
 /// row's own entries), the capsule button opens the shared list at the OWNER's effective scale
 /// (the kit's 0992 uiScale correction — the window rides SetScale) with the current value's
@@ -1647,10 +1697,11 @@ fn every_row_tooltip_key_resolves_in_the_real_global_strings() {
         );
         checked += 1;
     }
-    // 19 CVar rows (Social's two bubble switches are 1139's; Status Bar Text, Mouse Sensitivity
-    // and Max Camera Distance 1140's) + the Combat page's 14 saved-variable rows (1134) + the Interface
-    // page's 4 (3 from 1136, Buff Durations 1139) and the Action Bars page's 1 (1136).
-    assert_eq!(checked, 38, "every row but one carries a live 1.12 key");
+    // 20 CVar rows (Social's two bubble switches are 1139's; Status Bar Text, Mouse Sensitivity
+    // and Max Camera Distance 1140's; Graphics' Vertical Sync is 1394's) + the Combat page's 14
+    // saved-variable rows (1134) + the Interface page's 4 (3 from 1136, Buff Durations 1139) and
+    // the Action Bars page's 1 (1136).
+    assert_eq!(checked, 39, "every row but one carries a live 1.12 key");
     assert_eq!(
         untipped,
         vec!["ControlsRowAutoLoot".to_string()],
@@ -1739,10 +1790,10 @@ fn every_flavor_of_row_raises_its_plate_from_the_page_it_lives_on() {
             s.errors()
         );
     }
-    // 19 of the 20 CVar rows (Social's two are 1139's; Status Bar Text, Mouse Sensitivity and
-    // Max Camera Distance 1140's), plus the Combat page's 14 saved-variable rows (1134), the Interface page's 4
-    // (1136, + Buff Durations 1139) and Action Bars' 1 (1136).
-    assert_eq!(raised, 38, "every row but Auto Loot has a 1.12 description");
+    // 20 of the 21 CVar rows (Social's two are 1139's; Status Bar Text, Mouse Sensitivity and
+    // Max Camera Distance 1140's; Vertical Sync 1394's), plus the Combat page's 14 saved-variable
+    // rows (1134), the Interface page's 4 (1136, + Buff Durations 1139) and Action Bars' 1 (1136).
+    assert_eq!(raised, 39, "every row but Auto Loot has a 1.12 description");
 }
 
 /// The **Combat page** (decision 1134) — the first rows in this window whose store is a