fix: keep the dock's Close button reachable

The Close button followed focus, and moving the pointer down to the dock
moves focus off the popup. So the button disappeared somewhere on the
journey to it, and a secondary Chrome window could not be closed with a
mouse at all. Found on the endpoint; my fault.

The target is remembered instead. Once a secondary window has been
focused the dock keeps offering to close it, and losing focus — to the
dock, the main browser, a print dialog, any layer-shell surface —
changes nothing. It moves on only when that window closes or another
secondary takes over, and it falls back to another open secondary rather
than to nothing, so cancelling a print dialog leaves the render window
still closeable. It is chosen from the secondary list, which never
contains the first window, so it can never name the main browser.

Restoring the floating role to a window that already existed no longer
moves or focuses it. Moving it would undo wherever the teacher dragged
it; focusing it would raise the render window over the print dialog
sitting above it, which is one way the print flow was getting disturbed.

Verified by driving a real pointer through the exact path that was
broken: pointer over the popup, click to focus, then travel down to the
dock in steps, screenshotting throughout. The button is still there on
arrival, at 992,1041. Then the print flow: main browser, render window
and a separate Print dialog, pointer to the dock, button still there,
and killing the dialog leaves the render window as the new target with
the main browser untouched.

The button's own action could not be actuated in that harness, because
synthetic pointer input does not reach Wayland clients under headless
sway — the Browser button does not respond to it either. The action was
run directly instead, closing exactly the remembered container and
leaving main Chrome alive.

Co-Authored-By: Claude Opus 5 <[email protected]>

scripts/classroom-chrome-windows

@@ -84,11 +84,19 @@ def place(target):
     command(f"{target} move position center")
 
 
-def configure_secondary(identifier):
+def configure_secondary(identifier, arriving=True):
     """Float one exact container; never apply a broad Chrome float rule."""
     target = criterion(identifier)
     command(f"{target} floating enable")
     command(f"{target} border none")
+
+    if not arriving:
+        # Only restoring the floating role to a window that already
+        # existed. Never move it: that would undo wherever the teacher
+        # dragged it. Never focus it: that would raise the render window
+        # over the print dialog sitting above it.
+        return
+
     place(target)
     command(f"{target} focus")
 
@@ -97,19 +105,50 @@ def configure_secondary(identifier):
     place(target)
 
 
-def focused_secondary(secondary, chrome):
-    """The secondary window the dock's Close button should act on.
+class ActiveSecondary:
+    """The one secondary window the dock offers to close.
 
-    Only ever a focused one. If the teacher is in the main browser there is
-    nothing to close, and the dock shows no Close button at all.
+    Deliberately sticky. This used to be whichever secondary happened to
+    be focused, which made the button impossible to click: moving the
+    pointer down to the dock moves focus away from the popup, so the
+    button disappeared on the way to it. Nobody could ever reach it.
+
+    It is remembered instead. Losing focus changes nothing. It only
+    changes when the window it names goes away, or when another
+    secondary takes over by being focused.
     """
-    for identifier in secondary:
-        window = chrome.get(identifier)
 
-        if window and window["focused"] and not window["hidden"]:
-            return identifier
+    def __init__(self):
+        self.target = None
 
-    return None
+    def update(self, secondary, chrome):
+        # A focused secondary takes over. Focus on the dock, the print
+        # dialog, the main browser or any layer-shell surface is not a
+        # secondary, so none of them disturb this.
+        for identifier in secondary:
+            window = chrome.get(identifier)
+
+            if window and window["focused"] and not window["hidden"]:
+                self.target = identifier
+                break
+
+        # Never anything that has closed, and never the main browser:
+        # `secondary` cannot contain the primary.
+        if self.target is not None and self.target not in secondary:
+            self.target = None
+
+        # If the remembered window closed, fall back to another one that
+        # is still open, so cancelling a print dialog leaves the render
+        # window still closeable from the dock.
+        if self.target is None:
+            live = [
+                identifier
+                for identifier in secondary
+                if identifier in chrome and not chrome[identifier]["hidden"]
+            ]
+            self.target = live[-1] if live else None
+
+        return self.target
 
 
 def publish(target, path):
@@ -124,7 +163,7 @@ def publish(target, path):
               flush=True)
 
 
-def reconcile(roles, path):
+def reconcile(roles, active, path):
     current = windows()
     chrome = {window["id"]: window for window in chrome_windows(current)}
     changes = roles.update(current)
@@ -142,9 +181,9 @@ def reconcile(roles, path):
         window = chrome.get(identifier)
 
         if window and not window["hidden"] and not window["floating"]:
-            configure_secondary(identifier)
+            configure_secondary(identifier, arriving=False)
 
-    publish(focused_secondary(roles.secondary, chrome), path)
+    publish(active.update(roles.secondary, chrome), path)
 
 
 def subscribe():
@@ -170,11 +209,12 @@ def watch():
             return 0
 
         roles = ChromeRoles()
+        active = ActiveSecondary()
 
         try:
             while True:
                 # Whatever happened while there was no subscription.
-                reconcile(roles, path)
+                reconcile(roles, active, path)
 
                 stream = subscribe()
 
@@ -189,7 +229,7 @@ def watch():
                         continue
 
                     if event.get("change") in INTERESTING:
-                        reconcile(roles, path)
+                        reconcile(roles, active, path)
 
                 # Sway went away or restarted; wait, then pick it back up.
                 stream.wait()