Render panel header glyphs through the resolved-icon path (#8558)

Sources/Panels/FilePreviewPanel.swift

@@ -369,7 +369,6 @@ private struct FileExternalOpenHeaderMenuButton: View {
             PanelHeaderIconGlyph(systemName: "square.and.arrow.up")
         }
         .buttonStyle(.plain)
-        .foregroundColor(.secondary)
         .disabled(isDisabled)
         .help(helpText)
         .accessibilityLabel(helpText)

Sources/Panels/MarkdownTypographyControl.swift

@@ -45,7 +45,6 @@ struct MarkdownTypographyControl: View {
             PanelHeaderIconGlyph(systemName: "textformat.size")
         }
         .buttonStyle(.plain)
-        .foregroundColor(.secondary)
         .help(buttonLabel)
         .accessibilityLabel(buttonLabel)
         .popover(isPresented: $isPresented, arrowEdge: .bottom) {

Sources/Panels/PanelContentView.swift

@@ -382,9 +382,12 @@ struct PanelFilePathHeader<TrailingContent: View>: View {
 
     var body: some View {
         HStack(spacing: 8) {
-            CmuxSystemSymbolImage(systemName: iconSystemName, pointSize: 16)
-                .foregroundStyle(.secondary)
-                .frame(width: 16)
+            CmuxResolvedIconImage(request: CmuxResolvedIconRequest(
+                source: .systemSymbol(name: iconSystemName, accessibilityDescription: nil),
+                size: NSSize(width: 16, height: 16),
+                tintColor: PanelHeaderIconGlyph.tint(headerForeground: foregroundColor)
+            ))
+            .frame(width: 16, height: 16)
             Text(filePath)
                 .cmuxFont(size: 11, design: .monospaced)
                 .foregroundStyle(Color(nsColor: foregroundColor).opacity(0.68))
@@ -397,6 +400,7 @@ struct PanelFilePathHeader<TrailingContent: View>: View {
         .padding(.horizontal, 12)
         .frame(height: 30)
         .background(Color.clear)
+        .environment(\.panelHeaderIconTint, PanelHeaderIconGlyph.tint(headerForeground: foregroundColor))
     }
 }
 
@@ -411,19 +415,71 @@ struct PanelHeaderIconButton: View {
             PanelHeaderIconGlyph(systemName: systemName)
         }
         .buttonStyle(.plain)
-        .foregroundColor(.secondary)
         .disabled(isDisabled)
         .help(label)
         .accessibilityLabel(label)
     }
 }
 
+/// Panel-header glyph drawn through the appearance-resolved AppKit renderer.
+///
+/// The SwiftUI symbol path (`Image(systemName:)` and the shared template
+/// `NSImage` behind `CmuxSystemSymbolImage`) rasterizes fully transparent in
+/// this header on macOS 15 while the button keeps its frame and hit area, so
+/// the controls stay clickable but invisible (#8558, #8352, #7725, #4476).
+/// `CmuxResolvedIconRenderer` draws into an explicit bitmap context under the
+/// resolved appearance, verifies the output has visible pixels, and re-renders
+/// when the window or effective appearance changes.
 struct PanelHeaderIconGlyph: View {
     let systemName: String
+    @Environment(\.panelHeaderIconTint) private var headerTint
+    @Environment(\.isEnabled) private var isEnabled
 
     var body: some View {
-        CmuxSystemSymbolImage(systemName: systemName, pointSize: 13)
-            .frame(width: 20, height: 20, alignment: .center)
-            .contentShape(Rectangle())
+        CmuxResolvedIconImage(
+            request: Self.request(systemName: systemName, tint: headerTint, isEnabled: isEnabled)
+        )
+        .frame(width: 13, height: 13)
+        .frame(width: 20, height: 20, alignment: .center)
+        .contentShape(Rectangle())
+    }
+
+    /// Builds one header glyph's render request.
+    ///
+    /// The tint is always an explicit color rather than a semantic style: the
+    /// AppKit-backed icon resolves the window appearance, not the panel's
+    /// SwiftUI `colorScheme` override, so a hierarchical style would not track
+    /// the panel theme. Disabled glyphs keep the color and drop alpha.
+    @MainActor
+    static func request(systemName: String, tint: NSColor?, isEnabled: Bool) -> CmuxResolvedIconRequest {
+        let baseTint = tint ?? .secondaryLabelColor
+        let resolvedTint = isEnabled
+            ? baseTint
+            : baseTint.withAlphaComponent(baseTint.alphaComponent * 0.45)
+        return CmuxResolvedIconRequest(
+            source: .systemSymbol(name: systemName, accessibilityDescription: nil),
+            size: NSSize(width: 13, height: 13),
+            tintColor: resolvedTint
+        )
+    }
+
+    /// Secondary-emphasis tint derived from the header's theme foreground,
+    /// matching the emphasis the previous `.secondary` template tint produced.
+    static func tint(headerForeground: NSColor) -> NSColor {
+        headerForeground.withAlphaComponent(headerForeground.alphaComponent * 0.55)
+    }
+}
+
+/// Explicit glyph tint published by ``PanelFilePathHeader`` so header controls
+/// follow the panel's theme foreground. `nil` falls back to the
+/// appearance-resolved secondary label color.
+private struct PanelHeaderIconTintKey: EnvironmentKey {
+    static let defaultValue: NSColor? = nil
+}
+
+extension EnvironmentValues {
+    var panelHeaderIconTint: NSColor? {
+        get { self[PanelHeaderIconTintKey.self] }
+        set { self[PanelHeaderIconTintKey.self] = newValue }
     }
 }

cmux.xcodeproj/project.pbxproj

@@ -1546,6 +1546,7 @@ C0DE71B10000000000000001 /* AppDelegate+AgentChatNotifications.swift in Sources
 		D0B1001CA1B2C3D4E5F60001 /* PaneDropRoutingSupport.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B1001DA1B2C3D4E5F60001 /* PaneDropRoutingSupport.swift */; };
 		A5001400 /* Panel.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5001410 /* Panel.swift */; };
 		A5001405 /* PanelContentView.swift in Sources */ = {isa = PBXBuildFile; fileRef = A5001415 /* PanelContentView.swift */; };
+		C58558010000000000000001 /* PanelHeaderIconGlyphTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C58558010000000000000002 /* PanelHeaderIconGlyphTests.swift */; };
 		986900050000000000000001 /* PanelHost.swift in Sources */ = {isa = PBXBuildFile; fileRef = 986900050000000000000002 /* PanelHost.swift */; };
 		BB49DF25341706C2A892C27C /* PanelOwnedNativeViewSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE314D9700F6F1C8D4A2FE11 /* PanelOwnedNativeViewSession.swift */; };
 		C44550000000000000000001 /* PanelOwnedNativeViewSessionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C44550000000000000000002 /* PanelOwnedNativeViewSessionTests.swift */; };
@@ -4326,6 +4327,7 @@ C0DE71B10000000000000002 /* AppDelegate+AgentChatNotifications.swift */ = {isa =
 		D0B1001DA1B2C3D4E5F60001 /* PaneDropRoutingSupport.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PaneDropRoutingSupport.swift; sourceTree = "<group>"; };
 		A5001410 /* Panel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Panels/Panel.swift; sourceTree = "<group>"; };
 		A5001415 /* PanelContentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Panels/PanelContentView.swift; sourceTree = "<group>"; };
+		C58558010000000000000002 /* PanelHeaderIconGlyphTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PanelHeaderIconGlyphTests.swift; sourceTree = "<group>"; };
 		986900050000000000000002 /* PanelHost.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PanelHost.swift; sourceTree = "<group>"; };
 		CE314D9700F6F1C8D4A2FE11 /* PanelOwnedNativeViewSession.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Panels/PanelOwnedNativeViewSession.swift; sourceTree = "<group>"; };
 		C44550000000000000000002 /* PanelOwnedNativeViewSessionTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PanelOwnedNativeViewSessionTests.swift; sourceTree = "<group>"; };
@@ -7865,6 +7867,7 @@ C0DE71B10000000000000002 /* AppDelegate+AgentChatNotifications.swift */ = {isa =
 				D36A00020000000000000002 /* AgentHibernationTests.swift */,
 				D36A00050000000000000002 /* RendererRealizationPlannerTests.swift */,
 				C58410010000000000000002 /* RenderableSystemSymbolTests.swift */,
+				C58558010000000000000002 /* PanelHeaderIconGlyphTests.swift */,
 				DCDC0000000000000000B002 /* DockControlDefinitionDecodingTests.swift */,
 				859100000000000000000002 /* TerminalLinkOpenCoordinatorTests.swift */,
 				D7529002A1B2C3D4E5F60718 /* DockPaneDropUnfocusedRoutingTests.swift */,
@@ -11350,6 +11353,7 @@ C0DE71B10000000000000002 /* AppDelegate+AgentChatNotifications.swift */ = {isa =
 				9637C6D3170F4BE1A7EF6243 /* OmnibarSubmitDecisionTests.swift in Sources */,
 				0A0F00550000000000000001 /* OmpSupportTests.swift in Sources */,
 				A5E01203A1B2C3D4E5F60718 /* OpenCodeHookRegressionTests.swift in Sources */,
+				C58558010000000000000001 /* PanelHeaderIconGlyphTests.swift in Sources */,
 					C44550000000000000000001 /* PanelOwnedNativeViewSessionTests.swift in Sources */,
 					6313FACE0000000000000000 /* PaneMemoryGuardrailTests.swift in Sources */,
 				B88350000000000000000003 /* PasteboardThreadSignalingDataProvider.swift in Sources */,

cmuxTests/PanelHeaderIconGlyphTests.swift

@@ -0,0 +1,100 @@
+import AppKit
+import CmuxAppKitSupportUI
+import Testing
+
+#if canImport(cmux_DEV)
+@testable import cmux_DEV
+#elseif canImport(cmux)
+@testable import cmux
+#endif
+
+@MainActor
+@Suite("Panel header icon glyphs")
+struct PanelHeaderIconGlyphTests {
+    /// Every symbol the markdown viewer and file preview headers render.
+    private static let headerSymbols = [
+        "doc.richtext",
+        "textformat.size",
+        "arrow.clockwise",
+        "arrow.counterclockwise",
+        "square.and.arrow.down",
+        "square.and.arrow.up",
+        "doc.plaintext",
+        "doc.on.doc",
+        "chevron.left.forwardslash.chevron.right",
+        "eye",
+    ]
+
+    @Test func requestCarriesAnExplicitTintAtGlyphSize() {
+        let tint = NSColor.systemTeal
+        let request = PanelHeaderIconGlyph.request(systemName: "eye", tint: tint, isEnabled: true)
+
+        #expect(request.size == NSSize(width: 13, height: 13))
+        #expect(request.tintColor == tint)
+        guard case .systemSymbol(let name, _) = request.source else {
+            Issue.record("expected a system symbol source")
+            return
+        }
+        #expect(name == "eye")
+    }
+
+    @Test func requestFallsBackToSecondaryLabelWhenHeaderTintIsMissing() {
+        let request = PanelHeaderIconGlyph.request(systemName: "eye", tint: nil, isEnabled: true)
+
+        #expect(request.tintColor == NSColor.secondaryLabelColor)
+    }
+
+    @Test func disabledRequestKeepsTheColorAndDropsAlpha() throws {
+        let tint = NSColor.white.withAlphaComponent(0.8)
+        let request = PanelHeaderIconGlyph.request(systemName: "eye", tint: tint, isEnabled: false)
+        let resolved = try #require(request.tintColor)
+
+        #expect(abs(resolved.alphaComponent - 0.8 * 0.45) < 0.0001)
+    }
+
+    @Test func themeTintKeepsSecondaryEmphasis() {
+        let foreground = NSColor(calibratedWhite: 0.9, alpha: 1)
+        let tint = PanelHeaderIconGlyph.tint(headerForeground: foreground)
+
+        #expect(abs(tint.alphaComponent - 0.55) < 0.0001)
+    }
+
+    /// Regression guard for #8558: the SwiftUI symbol path rasterized these
+    /// glyphs fully transparent while their buttons stayed clickable. The
+    /// resolved renderer must produce visible pixels in either appearance.
+    @Test(arguments: headerSymbols)
+    func headerSymbolsRenderVisiblePixels(symbol: String) throws {
+        let renderer = CmuxResolvedIconRenderer()
+        let request = PanelHeaderIconGlyph.request(
+            systemName: symbol,
+            tint: PanelHeaderIconGlyph.tint(headerForeground: .white),
+            isEnabled: true
+        )
+
+        for appearanceName in [NSAppearance.Name.aqua, .darkAqua] {
+            let appearance = try #require(NSAppearance(named: appearanceName))
+            switch renderer.render(for: request, appearance: appearance) {
+            case .success(let image):
+                #expect(visiblePixelCount(in: image) > 0)
+            case .failure(let failure):
+                Issue.record("\(symbol) failed to render in \(appearanceName.rawValue): \(failure)")
+            }
+        }
+    }
+
+    private func visiblePixelCount(in image: NSImage) -> Int {
+        guard let cgImage = image.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
+            return 0
+        }
+        let representation = NSBitmapImageRep(cgImage: cgImage)
+        var count = 0
+        for y in 0..<representation.pixelsHigh {
+            for x in 0..<representation.pixelsWide {
+                if let color = representation.colorAt(x: x, y: y), color.alphaComponent > 0.01 {
+                    count += 1
+                }
+            }
+        }
+        return count
+    }
+}