fix(ui): follow-up fixes for the ascii_mode status icon

sources/SquirrelApplicationDelegate.swift

@@ -236,10 +236,13 @@ final class SquirrelApplicationDelegate: NSObject, NSApplicationDelegate, SPUSta
     notifCenter.addObserver(forName: .init("SquirrelSyncNotification"), object: nil, queue: nil, using: rimeNeedsSync)
     notifCenter.addObserver(forName: .init("SquirrelToggleASCIIModeNotification"), object: nil, queue: nil, using: rimeToggleASCIIMode)
     notifCenter.addObserver(forName: .init("SquirrelGetASCIIModeNotification"), object: nil, queue: nil, using: rimeGetASCIIMode)
-    notifCenter.addObserver(forName: .init(kTISNotifySelectedKeyboardInputSourceChanged as String), object: nil, queue: .main) { [weak self] _ in
-      self?.updateStatusItemVisibility()
-      self?.finalizeStrandedComposition()
-    }
+    // Suspension behavior matters: the default coalescing holds notifications
+    // back while the process is inactive, which is exactly the state Squirrel
+    // enters when the user switches away — the icon would fail to hide until
+    // the next activation. Deliver immediately instead.
+    notifCenter.addObserver(self, selector: #selector(inputSourceChanged(_:)),
+                            name: .init(kTISNotifySelectedKeyboardInputSourceChanged as String),
+                            object: nil, suspensionBehavior: .deliverImmediately)
   }
 
   func applicationShouldTerminate(_ sender: NSApplication) -> NSApplication.TerminateReply {
@@ -361,6 +364,13 @@ private extension SquirrelApplicationDelegate {
     updateStatusItemVisibility()
   }
 
+  @objc func inputSourceChanged(_: Notification) {
+    DispatchQueue.main.async { [weak self] in
+      self?.updateStatusItemVisibility()
+      self?.finalizeStrandedComposition()
+    }
+  }
+
   func updateStatusItemVisibility() {
     guard let statusItem = statusItem else { return }
     let currentInputSourceID = SquirrelInstaller.currentInputSourceID() ?? ""

sources/SquirrelInputController.swift

@@ -177,6 +177,30 @@
     if keyboardLayout != "" {
       client?.overrideKeyboard(withKeyboardNamed: keyboardLayout)
     }
+    // Switching to Squirrel produces no flagsChanged event, so a Caps Lock
+    // already engaged in the previous input source would go unnoticed by Rime.
+    // NSEvent.modifierFlags only reflects this process's own event stream and
+    // is stale here; query the session-wide hardware state instead.
+    let capsLockOn = CGEventSource.flagsState(.combinedSessionState).contains(.maskAlphaShift)
+    // Do NOT force ascii_mode from a pre-existing Caps Lock here: macOS clears
+    // Caps Lock whenever the input source changes, so a Caps Lock observed at
+    // activation is transient — acting on it raced against that clearing and
+    // left ascii_mode stuck on with no way for Rime to learn caps was dropped.
+    // Instead, only repaint the icon from the session's actual state; it may
+    // be stale because a fresh session created with switches/@N/reset: 1
+    // never fires an option notification.
+    if session != 0 && rimeAPI.find_session(session) {
+      let asciiMode = rimeAPI.get_option(session, "ascii_mode")
+      let label = "ascii_mode".withCString { name in
+        rimeAPI.get_state_label_abbreviated(session, name, asciiMode, true).asString
+      }
+      NSApp.squirrelAppDelegate.updateStatusIcon(asciiMode: asciiMode, schemaLabel: label)
+    }
+    if capsLockOn {
+      lastModifiers.insert(.capsLock)
+    } else {
+      lastModifiers.remove(.capsLock)
+    }
     preedit = ""
     if session != 0 {
       let state = rimeAPI.get_option(session, "ascii_mode")
@@ -434,7 +458,7 @@
   }
 
   // Preserve reserved comment marks when librime requests a UI-only refresh.
   func rimeUpdate(clearReservedComments: Bool = true) {
     if clearReservedComments {
       specialCommentIndices = [:]
     }