Seat: keep parent Xwayland view of a focused OR surface activated

Xwayland OR menus may disappear if their parent view is deactivated. The
heuristic and ICCCM input model implemented prior, used to determine whether an
OR surface may take focus, does not cover all menus, so retaining parent view
activation works as a catch-all solution for handling unwanted OR menu focus.

 river/Seat.zig         | 36 ++++++++++++++++++++++++++++++++++--
 river/XwaylandView.zig | 10 ++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/river/Seat.zig b/river/Seat.zig
index 627e2f9..441ede3 100644
--- a/river/Seat.zig
+++ b/river/Seat.zig
@@ -80,6 +80,9 @@ focused_output: *Output,
 
 focused: FocusTarget = .none,
 
+/// Currently activated Xwayland view (used to handle override redirect menus)
+activated_xwayland_view: if (build_options.xwayland) ?*View else void = if (build_options.xwayland) null else {},
+
 /// Stack of views in most recently focused order
 /// If there is a currently focused view, it is on top.
 focus_stack: ViewStack(*View) = .{},
@@ -230,11 +233,36 @@ pub fn setFocusRaw(self: *Self, new_focus: FocusTarget) void {
         .none => null,
     };
 
+    if (build_options.xwayland) {
+        // Keep the parent top-level Xwayland view of any override redirect surface
+        // activated while that override redirect surface is focused. This ensures
+        // override redirect menus do not disappear as a result of deactivating
+        // their parent window.
+        if (new_focus == .xwayland_override_redirect and
+            self.focused == .view and
+            self.focused.view.impl == .xwayland_view and
+            self.focused.view.impl.xwayland_view.xwayland_surface.pid == new_focus.xwayland_override_redirect.xwayland_surface.pid)
+        {
+            self.activated_xwayland_view = self.focused.view;
+        } else if (self.activated_xwayland_view) |active_view| {
+            if (!(new_focus == .view and new_focus.view == active_view) and
+                !(new_focus == .xwayland_override_redirect and new_focus.xwayland_override_redirect.xwayland_surface.pid == active_view.impl.xwayland_view.xwayland_surface.pid))
+            {
+                if (active_view.pending.focus == 0) active_view.setActivated(false);
+                self.activated_xwayland_view = null;
+            }
+        }
+    }
+
     // First clear the current focus
     switch (self.focused) {
         .view => |view| {
             view.pending.focus -= 1;
-            if (view.pending.focus == 0) view.setActivated(false);
+            if (view.pending.focus == 0 and
+                (!build_options.xwayland or view != self.activated_xwayland_view))
+            {
+                view.setActivated(false);
+            }
         },
         .xwayland_override_redirect, .layer, .lock_surface, .none => {},
     }
@@ -244,7 +272,11 @@ pub fn setFocusRaw(self: *Self, new_focus: FocusTarget) void {
         .view => |target_view| {
             assert(server.lock_manager.state == .unlocked);
             assert(self.focused_output == target_view.output);
-            if (target_view.pending.focus == 0) target_view.setActivated(true);
+            if (target_view.pending.focus == 0 and
+                (!build_options.xwayland or target_view != self.activated_xwayland_view))
+            {
+                target_view.setActivated(true);
+            }
             target_view.pending.focus += 1;
             target_view.pending.urgent = false;
         },
diff --git a/river/XwaylandView.zig b/river/XwaylandView.zig
index 0eef7a4..55681e6 100644
--- a/river/XwaylandView.zig
+++ b/river/XwaylandView.zig
@@ -175,6 +175,16 @@ pub fn getConstraints(self: Self) View.Constraints {
 /// Called when the xwayland surface is destroyed
 fn handleDestroy(listener: *wl.Listener(*wlr.XwaylandSurface), _: *wlr.XwaylandSurface) void {
     const self = @fieldParentPtr(Self, "destroy", listener);
+    const view = self.view;
+
+    // Ensure no seat will attempt to access this view after it is destroyed.
+    var seat_it = server.input_manager.seats.first;
+    while (seat_it) |seat_node| : (seat_it = seat_node.next) {
+        const seat = &seat_node.data;
+        if (seat.activated_xwayland_view == view) {
+            seat.activated_xwayland_view = null;
+        }
+    }
 
     // Remove listeners that are active for the entire lifetime of the view
     self.destroy.link.remove();