diff --git a/src/AcDream.Plugins.MossTank/MossTankPanel.cs b/src/AcDream.Plugins.MossTank/MossTankPanel.cs
index 696e9a54..84c359c1 100644
--- a/src/AcDream.Plugins.MossTank/MossTankPanel.cs
+++ b/src/AcDream.Plugins.MossTank/MossTankPanel.cs
@@ -1040,6 +1040,18 @@ internal sealed partial class MossTankPanel
     // PluginCore.cs:3576-3599 — any cell click deletes the waypoint).
     public IReadOnlyList<string> RouteWaypointTextColumn => _routeRows;
     public IReadOnlyList<string> RouteWaypointCountColumn => _routeWaypointCounts;
+    // Round F item 6 (resemblance re-check: "Route's count column
+    // squeezes to 17 when the list scrolls"): RouteWaypointCountColumn
+    // was the grid's LAST column, so docs/plugin-ui-markup.md's own
+    // "Width semantics" rule made its declared width="30" NEVER validated
+    // or used — it silently absorbed whatever remainder was left instead
+    // (33px normally, but only 17px once the scrollbar's own 16px
+    // reservation ate into that remainder). A trailing filler column
+    // (empty items) now sits after it so the count column is no longer
+    // last and keeps its own real, always-honored 30px width — the same
+    // fix as the Monsters grid's MonsterFillerColumn.
+    public IReadOnlyList<string> RouteWaypointFillerColumn => Array.Empty<string>();
+    public Action<int> RouteWaypointFillerClick => static _ => { };
     public Action<int> DeleteRouteWaypointAt => DeleteRouteWaypointAtCore;
     public Action SelectNearestRouteWaypoint => SelectNearestRouteWaypointCore;
     // VTank's own cmbNavType captions read Circular/Linear/Follow/Once
diff --git a/src/AcDream.Plugins.MossTank/mosstank-loot-editor.xml b/src/AcDream.Plugins.MossTank/mosstank-loot-editor.xml
index be38d697..97c213f7 100644
--- a/src/AcDream.Plugins.MossTank/mosstank-loot-editor.xml
+++ b/src/AcDream.Plugins.MossTank/mosstank-loot-editor.xml
@@ -13,11 +13,20 @@
   panel, registered as a THIRD AddPanel call from MossTankPlugin.cs with
   ShowInSidePanel=false (VTank's popup has no independent shelf entry). This
   panel's own visible="{LootEditorVisible}" binding is the SAME flag the
-  checkbox flips and this popup's own "Back" button clears
+  checkbox flips and CloseLootEditor clears
   (CloseLootEditor => _lootEditorVisible = false) — closing the popup
   unchecks the box for free (see mosstank-advanced.xml's comment for why no
   new host show/hide API was needed).
 
+  Round F item 6 (resemblance re-check: "Loot Editor: drop the leftover
+  'Back' button — the window closes from its title bar like the
+  others"): the standalone "Back" button bound directly to
+  CloseLootEditor is gone — the window's own OS-level title bar already
+  closes it, the same shape every other plugin popup (Advanced Options
+  included) has used with no Back button of its own since round D.
+  CloseLootEditor stays real: ToggleLootEditorVisible (the Profiles-tab
+  "Show Editor" checkbox's own close path) still calls it directly.
+
   Fix round A also replaced the "↑"/"↓" text buttons (MoveLootRuleUp/Down)
   with the same DAT move-up/move-down icon glyphs the Monsters grid already
   uses (0x060028FC / 0x060028FD) — the retail default UI font (0x40000000)
@@ -40,8 +49,6 @@
 -->
 <panel x="660" y="405" w="268" h="300" title="MossTank Loot Editor"
        visible="{LootEditorVisible}" resize="none">
-  <button x="198" y="2" w="64" h="18" text="Back"
-          onclick="{CloseLootEditor}" />
   <field x="4" y="22" w="260" h="18" text="{LootProfileNameDraft}"
          onchange="{SetLootProfileNameDraft}"
          onsubmit="{CreateNamedLootProfile}" maxlength="64"
diff --git a/src/AcDream.Plugins.MossTank/mosstank.xml b/src/AcDream.Plugins.MossTank/mosstank.xml
index 7387a9c4..4f93e083 100644
--- a/src/AcDream.Plugins.MossTank/mosstank.xml
+++ b/src/AcDream.Plugins.MossTank/mosstank.xml
@@ -582,13 +582,42 @@
        catches. Both lists are restored to VTank's full 320x116 at the far
        left (x=4) and far right (x=524, 848-4-320) with their own
        120-wide "Add..." row below each list; the whole MossTank-extras
-       block moves into the EMPTY MIDDLE strip between the two lists
-       (x=332..516, the 184px VTank's own layout never uses), stacked
-       compactly: 7 toggles at a 16px pitch, then Difficulty +/-, then
-       Rebuff +/-, then the Buff button + status, then Coverage at y=178
-       (194-16, item 3's bottom-fit rule) — a proportion-preserving
-       compromise fitting a real 184x194 box, not a pixel-for-pixel VVS
-       port (owner's bar: "looks basically the same", never VVS pixels). -->
+       block moves into the EMPTY MIDDLE strip between the two lists,
+       stacked compactly: 7 toggles at a 16px pitch, then Difficulty +/-,
+       then Rebuff +/-, then the Buff button + status, then Coverage
+       right under it — a proportion-preserving compromise fitting a
+       real box, not a pixel-for-pixel VVS port (owner's bar: "looks
+       basically the same", never VVS pixels).
+
+       Round F item 6 (resemblance re-check: "Buffs' 136 px middle gap
+       and the orphaned Coverage label"). Coverage moved from y=213
+       (anchored to the group's bottom edge, a real 55px empty hole
+       above it once the panel grew past its original 194-tall size) to
+       sit directly under the Buff button row instead — no anchor, since
+       nothing below it needs the space that anchor used to protect.
+
+       The middle-gap half of this item turned out to have a hard
+       geometric ceiling: Extra Buff Spells never moves (anchor="left
+       top bottom", pinned at x=4..324) but Blacklisted Buff Families
+       tracks the growing right edge (anchor="right"), sitting at
+       x=524 at the panel's own tested floor (856x236, PanelIsResizable
+       FlooredAtThePreRoundDAuthoredSize) and x=652 at the 984-wide
+       enlarged default — a 128px swing. The extras strip (182px wide)
+       is a single FIXED position, so it can only be centered relative
+       to ONE of those two widths; centering it against the 984 default
+       (x=397) put its right edge at 579, 55px INSIDE where the same
+       list sits at the floor (524) — a real overlap
+       ResolvedMainPanelHasNoOverlapOrOutOfBoundsChildAtThisSize's own
+       856x236 case catches. x=333 is the strip's floor-centered
+       position (9px margin on both sides against the floor's 324..524
+       gap, the widest safe position a fixed strip can take) — the same
+       position fix round B item 2 effectively already used (x=332, 1px
+       off from exactly centered) before Round D's enlargement existed.
+       The residual asymmetric gap at the 984 default (previously ~8/138,
+       now ~9/137) is therefore an accepted, unavoidable-without-a-
+       redesign limitation — the same "dead margin, polish later" trade
+       the resemblance re-check already accepted for six other tabs at
+       this same enlarged size. -->
   <group x="8" y="42" w="976" h="229" visible="{BuffsVisible}" anchor="left top right bottom">
     <!-- Fix round B item 14 (owner honesty rule): BuffPlan.Build does not
          read this set at all yet — a real, tracked wiring gap (see
@@ -616,39 +645,39 @@
           onchange="{DeleteBlacklistedBuffFamilyAt}" tooltip="Click a row to remove it." />
     <button x="652" y="173" w="120" h="18" text="Add..." onclick="{ShowBlacklistedBuffPicker}" anchor="right bottom" />
 
-    <toggle x="332" y="0" w="180" h="16" text="Trained skills only"
+    <toggle x="333" y="0" w="180" h="16" text="Trained skills only"
             checked="{TrainedOnlyEnabled}" onclick="{ToggleTrainedOnly}" />
-    <toggle x="332" y="16" w="180" h="16" text="Attributes"
+    <toggle x="333" y="16" w="180" h="16" text="Attributes"
             checked="{AttributesEnabled}" onclick="{ToggleAttributes}" />
-    <toggle x="332" y="32" w="180" h="16" text="Protections"
+    <toggle x="333" y="32" w="180" h="16" text="Protections"
             checked="{ProtectionsEnabled}" onclick="{ToggleProtections}" />
-    <toggle x="332" y="48" w="180" h="16" text="Weapon auras"
+    <toggle x="333" y="48" w="180" h="16" text="Weapon auras"
             checked="{AurasEnabled}" onclick="{ToggleAuras}" />
-    <toggle x="332" y="64" w="180" h="16" text="Armor banes"
+    <toggle x="333" y="64" w="180" h="16" text="Armor banes"
             checked="{BanesEnabled}" onclick="{ToggleBanes}" />
-    <toggle x="332" y="80" w="180" h="16" text="Regeneration"
+    <toggle x="333" y="80" w="180" h="16" text="Regeneration"
             checked="{RegenerationEnabled}" onclick="{ToggleRegeneration}" />
-    <toggle x="332" y="96" w="180" h="16" text="Other self-spells"
+    <toggle x="333" y="96" w="180" h="16" text="Other self-spells"
             checked="{OtherEnabled}" onclick="{ToggleOther}" />
 
-    <label x="332" y="116" w="140" text="{DifficultyText}" color="#FFE8DEC3" />
-    <button x="472" y="112" w="20" h="18" text="-" onclick="{DifficultyDown}"
+    <label x="333" y="116" w="140" text="{DifficultyText}" color="#FFE8DEC3" />
+    <button x="473" y="112" w="20" h="18" text="-" onclick="{DifficultyDown}"
             tooltip="Decrease the skill-over-difficulty margin." />
-    <button x="494" y="112" w="20" h="18" text="+" onclick="{DifficultyUp}"
+    <button x="495" y="112" w="20" h="18" text="+" onclick="{DifficultyUp}"
             tooltip="Increase the skill-over-difficulty margin." />
-    <label x="332" y="136" w="140" text="{RebuffText}" color="#FFE8DEC3" />
-    <button x="472" y="132" w="20" h="18" text="-" onclick="{RebuffDown}"
+    <label x="333" y="136" w="140" text="{RebuffText}" color="#FFE8DEC3" />
+    <button x="473" y="132" w="20" h="18" text="-" onclick="{RebuffDown}"
             tooltip="Rebuff later." />
-    <button x="494" y="132" w="20" h="18" text="+" onclick="{RebuffUp}"
+    <button x="495" y="132" w="20" h="18" text="+" onclick="{RebuffUp}"
             tooltip="Rebuff earlier." />
 
-    <button x="332" y="154" w="110" h="18" text="{BuffButtonText}" onclick="{Buff}" />
-    <label x="446" y="158" w="70" text="{BuffStatus}" color="#FFC7B98F" />
-    <!-- Round D item 4: the "bottom-fit rule" the original comment names
-         (194-16) now targets the enlarged group's own bottom edge
-         (229-16), anchor="bottom" so a further manual resize keeps it
-         pinned there. -->
-    <label x="332" y="213" w="184" h="16" text="{Coverage}" color="#FF9B9072" anchor="bottom" />
+    <button x="333" y="154" w="110" h="18" text="{BuffButtonText}" onclick="{Buff}" />
+    <label x="447" y="158" w="70" text="{BuffStatus}" color="#FFC7B98F" />
+    <!-- Round F item 6: sits right under the button row above (154+18=172,
+         +4px) instead of anchored to the group's bottom edge — the
+         anchor used to leave a growing empty hole (55px at the enlarged
+         984-wide default) between this label and the row it belongs to. -->
+    <label x="333" y="176" w="184" h="16" text="{Coverage}" color="#FF9B9072" />
   </group>
 
   <!-- Route: VTank's own 2-across button grid, row order, and bottom
@@ -657,7 +686,13 @@
        verbatim, +4px left margin for our own convention). The waypoint
        list is VTank's own clWP/clWPc 2-column grid (Campaign VT S7.5;
        PluginCore.cs:3576-3599 — any cell click deletes the waypoint).
-       PITCH: text 330+7=337, count (last column) auto.
+       PITCH: text was 330+7=337, count 23+7=30. Round F item 6 narrowed
+       text to 324 (337+30=367 already exceeded this list's own
+       w=370 minus the scrollbar's 16px reservation — 354 — so count
+       was clamped to 17px the moment the list actually needed to
+       scroll) and appended a third, trailing filler column so count is
+       no longer the grid's LAST column and keeps its declared 30px
+       honored instead of silently absorbed/starved.
 
        MossTank-only extras that have no VTank Route-tab counterpart moved
        to the Advanced Options popup's own "MossTank Extras" section:
@@ -686,8 +721,19 @@
     <list x="4" y="16" w="370" h="151" rowheight="17" anchor="left top bottom"
           selected="{SelectedRouteWaypointIndex}" onchange="{SelectRouteWaypoint}"
           tooltip="Click a waypoint to remove it.">
-      <column type="text" width="337" items="{RouteWaypointTextColumn}" onclick="{DeleteRouteWaypointAt}" />
+      <column type="text" width="324" items="{RouteWaypointTextColumn}" onclick="{DeleteRouteWaypointAt}" />
       <column type="text" width="30" items="{RouteWaypointCountColumn}" onclick="{DeleteRouteWaypointAt}" />
+      <!-- Round F item 6: a trailing filler so the count column above is
+           no longer the grid's LAST column and keeps its own real 30px
+           width instead of silently absorbing whatever's left. The text
+           column is also narrowed 337->324: 324+30=354 exactly matches
+           this list's own w=370 minus the scrollbar's 16px reservation,
+           so the count column gets its full 30px whether or not the
+           scrollbar is showing — previously 337+30=367 already exceeded
+           354, so the count column was clamped to 17px the moment the
+           list actually needed to scroll, no matter which column was
+           "last". -->
+      <column type="text" width="*" items="{RouteWaypointFillerColumn}" onclick="{RouteWaypointFillerClick}" />
     </list>
 
     <menu x="4" y="171" w="80" h="16" items="{RouteModeNames}" anchor="bottom"
diff --git a/tests/AcDream.App.Tests/UI/MarkupListColumnsTests.cs b/tests/AcDream.App.Tests/UI/MarkupListColumnsTests.cs
index d44c9405..77f4d3ab 100644
--- a/tests/AcDream.App.Tests/UI/MarkupListColumnsTests.cs
+++ b/tests/AcDream.App.Tests/UI/MarkupListColumnsTests.cs
@@ -1460,6 +1460,58 @@ public sealed class MarkupListColumnsTests
         Assert.Equal(new[] { 0 }, binding.ActionClicks);
     }
 
+    private sealed class RouteShapedBinding
+    {
+        public IReadOnlyList<string> Names { get; } =
+            Enumerable.Range(0, 9).Select(static i => $"WP{i}").ToArray();
+        public IReadOnlyList<string> Counts { get; } =
+            Enumerable.Range(0, 9).Select(static i => i.ToString()).ToArray();
+        public IReadOnlyList<string> Filler { get; } = Array.Empty<string>();
+        public int Selected { get; set; } = -1;
+        public Action<int> Click => static _ => { };
+    }
+
+    /// <summary>
+    /// Round F item 6 (resemblance re-check: "Route's count column
+    /// squeezes to 17 when the list scrolls"). Mirrors the Route tab's
+    /// EXACT real shape (mosstank.xml: a 370px-wide list, columns
+    /// 324/30/*) with enough rows (9, past the 151/17≈8 visible-row
+    /// ceiling) to force the scrollbar — the count column's declared
+    /// 30px was previously only honored while the scrollbar was hidden;
+    /// with it showing, 337(the OLD text width)+30 already exceeded
+    /// 370-16=354, clamping the count column to 17px. Reflects into
+    /// UiMarkupList's own cached column layout (the same one
+    /// DrawColumns/OnEventColumns use) rather than measuring glyphs —
+    /// this is a pure geometry question, no font involved.
+    /// </summary>
+    [Fact]
+    public void RouteShapedGrid_CountColumnStaysThirtyPxWhenTheListScrolls()
+    {
+        var binding = new RouteShapedBinding();
+        const string xml =
+            "<panel x=\"0\" y=\"0\" w=\"400\" h=\"200\">" +
+            "<list x=\"0\" y=\"0\" w=\"370\" h=\"151\" rowheight=\"17\" " +
+            "selected=\"{Selected}\">" +
+            "  <column type=\"text\" width=\"324\" items=\"{Names}\" onclick=\"{Click}\"/>" +
+            "  <column type=\"text\" width=\"30\" items=\"{Counts}\" onclick=\"{Click}\"/>" +
+            "  <column type=\"text\" width=\"*\" items=\"{Filler}\"/>" +
+            "</list></panel>";
+
+        var panel = MarkupDocument.Build(xml, binding, Sprite);
+        var list = Assert.IsType<UiMarkupList>(panel.Children[0]);
+
+        var (renderer, ctx) = MakeContext(800f, 400f);
+        list.DrawSelfAndChildren(ctx);
+
+        System.Reflection.FieldInfo layoutField = typeof(UiMarkupList).GetField(
+            "_cachedLayout",
+            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)!;
+        var layout = ((float x, float w)[])layoutField.GetValue(list)!;
+
+        Assert.Equal(3, layout.Length);
+        Assert.Equal(30f, layout[1].w, 3);
+    }
+
     private sealed class MonsterShapedBinding
     {
         public IReadOnlyList<bool> Checks { get; } = new[] { true, false };
diff --git a/tests/AcDream.App.Tests/UI/MossTankMarkupBuildOverRealFilesTests.cs b/tests/AcDream.App.Tests/UI/MossTankMarkupBuildOverRealFilesTests.cs
index 91b59e58..b1f9cac9 100644
--- a/tests/AcDream.App.Tests/UI/MossTankMarkupBuildOverRealFilesTests.cs
+++ b/tests/AcDream.App.Tests/UI/MossTankMarkupBuildOverRealFilesTests.cs
@@ -254,6 +254,73 @@ public sealed class MossTankMarkupBuildOverRealFilesTests
         }
     }
 
+    /// <summary>
+    /// Round F item 6 (resemblance re-check: "Buffs' 136 px middle gap").
+    /// <see cref="ResolvedMainPanelHasNoOverlapOrOutOfBoundsChildAtThisSize"/>
+    /// already proves the extras strip never overlaps the Blacklisted
+    /// Buff Families list at the floor or the enlarged size (that generic
+    /// sibling-overlap pass is exactly what caught the original x=397
+    /// attempt at true 984-default centering colliding with the list's
+    /// own floor position, x=524). This is the narrower, POSITIVE claim
+    /// that overlap pass alone doesn't make: the strip is actually
+    /// CENTERED at the panel's floor (856x236) — the one width at which
+    /// centering and non-overlap can both hold, since Extra Buff Spells
+    /// never moves but Blacklisted Buff Families tracks the growing
+    /// right edge.
+    /// </summary>
+    [Fact]
+    public void BuffsExtrasStripStaysCenteredAndNonOverlappingAtTheFloor()
+    {
+        string xml = File.ReadAllText(
+            Path.Combine(MossTankMarkupDirectory, "mosstank.xml"));
+        var panel = new MossTankPanel(new StubHost());
+
+        UiNineSlicePanel built = MarkupDocument.Build(xml, panel, static id => (id, 32, 32));
+
+        UiPanel[] tabGroups = built.Children
+            .Where(static child => child.GetType() == typeof(UiPanel))
+            .Cast<UiPanel>()
+            .ToArray();
+        Assert.Equal(9, tabGroups.Length);
+        foreach (UiPanel group in tabGroups)
+            group.Visible = false;
+        UiPanel buffsGroup = tabGroups[6];
+        buffsGroup.Visible = true;
+
+        var device = new RecordingGpuDevice();
+        var renderer = new TextRenderer(device, new NullGpuFrameSource(), "unused");
+        renderer.Begin(new Vector2(1400f, 900f));
+        var ctx = new UiRenderContext(renderer, new Vector2(1400f, 900f));
+
+        // First draw at the authored default captures anchor baselines;
+        // only then resize down to the panel's own tested floor.
+        built.DrawSelfAndChildren(ctx);
+        built.Width = 856f;
+        built.Height = 236f;
+        built.DrawSelfAndChildren(ctx);
+
+        UiMarkupList[] lists = buffsGroup.Children.OfType<UiMarkupList>().ToArray();
+        Assert.Equal(2, lists.Length);
+        UiMarkupList leftList = lists.Single(static l => l.Left < 300f);
+        UiMarkupList rightList = lists.Single(static l => l.Left >= 300f);
+
+        UiMarkupToggle trainedToggle = Assert.Single(
+            buffsGroup.Children.OfType<UiMarkupToggle>(), static t => t.Text == "Trained skills only");
+        UiSimpleButton rebuffUpButton = Assert.Single(
+            buffsGroup.Children.OfType<UiSimpleButton>(), static b => b.Text == "+" && b.Top > 120f);
+
+        float leftMargin = trainedToggle.Left - (leftList.Left + leftList.Width);
+        float rightMargin = rightList.Left - (rebuffUpButton.Left + rebuffUpButton.Width);
+        Assert.True(
+            rightMargin >= 0f,
+            $"Extras strip (right edge {rebuffUpButton.Left + rebuffUpButton.Width}) "
+            + $"overlaps the right list (left edge {rightList.Left}) at the floor.");
+        Assert.True(
+            MathF.Abs(leftMargin - rightMargin) <= 4f,
+            $"Extras strip not centered at the floor: left margin "
+            + $"{leftMargin}px, right margin {rightMargin}px.");
+    }
+
     private static void AssertResolvedWithinParent(UiElement parent)
     {
         foreach (UiElement child in parent.Children)
diff --git a/tests/AcDream.Plugins.MossTank.Tests/MossTankMarkupContractTests.cs b/tests/AcDream.Plugins.MossTank.Tests/MossTankMarkupContractTests.cs
index 5e1aa3b2..3c4142c5 100644
--- a/tests/AcDream.Plugins.MossTank.Tests/MossTankMarkupContractTests.cs
+++ b/tests/AcDream.Plugins.MossTank.Tests/MossTankMarkupContractTests.cs
@@ -301,6 +301,102 @@ public sealed class MossTankMarkupContractTests
         Assert.DoesNotContain("{ProfileNotice}", labelBindings);
     }
 
+    /// <summary>
+    /// Round F item 6 (resemblance re-check nits: "Buffs' 136 px middle
+    /// gap and the orphaned Coverage label"). Coverage sits right under
+    /// the Buff button row instead of anchored to the group's bottom
+    /// edge, which used to leave a 55px empty hole above it as the panel
+    /// grew.
+    ///
+    /// The middle-gap half has a hard geometric ceiling documented at
+    /// mosstank.xml's own Buffs comment: Extra Buff Spells never moves
+    /// (x=4..324) but Blacklisted Buff Families tracks the growing right
+    /// edge (anchor="right"), sitting at x=524 at the panel's own tested
+    /// FLOOR (856x236) and x=652 (its authored declaration below) at the
+    /// 984-wide enlarged default — a 128px swing this campaign's own
+    /// Round D item 4 introduced. A single FIXED-position strip can only
+    /// be centered relative to ONE of those two widths; centering
+    /// against the 984 default would put the strip's right edge INSIDE
+    /// where the list sits at the floor — a real overlap
+    /// ResolvedMainPanelHasNoOverlapOrOutOfBoundsChildAtThisSize's own
+    /// 856x236 case would catch. This pins centering against the FLOOR
+    /// value instead (declared x minus the 128px Round D growth delta —
+    /// 984-856) — the widest safe position a fixed strip can take,
+    /// verified against the real-file resolved tree at both sizes by
+    /// <c>MossTankMarkupBuildOverRealFilesTests.BuffsExtrasStripStaysCenteredAndNonOverlappingAtTheFloor</c>
+    /// in the App test project.
+    /// </summary>
+    [Fact]
+    public void BuffsExtrasStripIsCenteredAtThePanelsFloorAndCoverageSitsUnderTheButtonRow()
+    {
+        XDocument document = XDocument.Load(
+            Path.Combine(AppContext.BaseDirectory, "mosstank.xml"));
+        XElement root = Assert.IsType<XElement>(document.Root);
+        XElement buffsGroup = root.Elements("group")
+            .Single(static g => (string?)g.Attribute("visible") == "{BuffsVisible}");
+
+        XElement[] lists = buffsGroup.Elements("list").ToArray();
+        Assert.Equal(2, lists.Length);
+        float leftListRightEdge = Number(lists[0], "x") + Number(lists[0], "w");
+        // Round D item 4's own +128 growth: the declared x below is the
+        // 984-wide authored default; subtracting it back out gives the
+        // resolved position at the panel's tested floor (856x236).
+        const float roundDGrowthDelta = 984f - 856f;
+        float rightListLeftEdgeAtFloor = Number(lists[1], "x") - roundDGrowthDelta;
+
+        XElement trainedToggle = buffsGroup.Elements("toggle")
+            .Single(static t => (string?)t.Attribute("onclick") == "{ToggleTrainedOnly}");
+        XElement rebuffUpButton = buffsGroup.Elements("button")
+            .Single(static b => (string?)b.Attribute("onclick") == "{RebuffUp}");
+        float extrasLeft = Number(trainedToggle, "x");
+        float extrasRight = Number(rebuffUpButton, "x") + Number(rebuffUpButton, "w");
+
+        float leftMargin = extrasLeft - leftListRightEdge;
+        float rightMarginAtFloor = rightListLeftEdgeAtFloor - extrasRight;
+        Assert.True(
+            rightMarginAtFloor >= 0f,
+            $"Extras strip (right edge {extrasRight}) overlaps the "
+            + $"Blacklisted Buff Families list at the panel's floor "
+            + $"(left edge {rightListLeftEdgeAtFloor}).");
+        Assert.True(
+            MathF.Abs(leftMargin - rightMarginAtFloor) <= 4f,
+            $"Extras strip not centered at the panel's floor: left margin "
+            + $"{leftMargin}px, right margin {rightMarginAtFloor}px.");
+
+        XElement buffButton = buffsGroup.Elements("button")
+            .Single(static b => (string?)b.Attribute("onclick") == "{Buff}");
+        XElement coverage = buffsGroup.Elements("label")
+            .Single(static l => (string?)l.Attribute("text") == "{Coverage}");
+        float rowBottom = Number(buffButton, "y") + Number(buffButton, "h");
+        float coverageGap = Number(coverage, "y") - rowBottom;
+        Assert.True(
+            coverageGap is >= 0f and <= 12f,
+            $"Coverage sits {coverageGap}px below the Buff button row — "
+            + "expected <=12px, not the old 55px hole from anchoring it to "
+            + "the group's bottom edge instead.");
+    }
+
+    /// <summary>
+    /// Round F item 6 (resemblance re-check: "Loot Editor: drop the
+    /// leftover 'Back' button — the window closes from its title bar
+    /// like the others"). The standalone button is gone;
+    /// CloseLootEditor stays a real, bound property (still called by
+    /// ToggleLootEditorVisible, the Profiles-tab checkbox's own close
+    /// path).
+    /// </summary>
+    [Fact]
+    public void LootEditorHasNoLeftoverBackButton()
+    {
+        XDocument document = XDocument.Load(
+            Path.Combine(AppContext.BaseDirectory, "mosstank-loot-editor.xml"));
+        XElement root = Assert.IsType<XElement>(document.Root);
+
+        Assert.DoesNotContain(
+            root.Elements("button"),
+            static b => (string?)b.Attribute("text") == "Back");
+        Assert.NotNull(typeof(MossTankPanel).GetProperty("CloseLootEditor"));
+    }
+
     [Fact]
     public void AuthoredShellFitsTheMinimumCanvasAndEverySizedChildFitsItsParent()
     {