render: track subsurfaces created before role assignment

 river/LayerSurface.zig |  5 +++++
 river/Subsurface.zig   |  5 +++++
 river/XdgPopup.zig     |  5 +++++
 river/XdgToplevel.zig  | 15 ++++++++++-----
 4 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/river/LayerSurface.zig b/river/LayerSurface.zig
index 2968895..3031cee 100644
--- a/river/LayerSurface.zig
+++ b/river/LayerSurface.zig
@@ -69,6 +69,11 @@ pub fn init(self: *Self, output: *Output, wlr_layer_surface: *wlr.LayerSurfaceV1
     wlr_layer_surface.events.unmap.add(&self.unmap);
     wlr_layer_surface.events.new_popup.add(&self.new_popup);
     wlr_layer_surface.surface.events.new_subsurface.add(&self.new_subsurface);
+
+    // There may already be subsurfaces present on this surface that we
+    // aren't aware of and won't receive a new_subsurface event for.
+    var it = wlr_layer_surface.surface.subsurfaces.iterator(.forward);
+    while (it.next()) |s| Subsurface.create(s, .{ .layer_surface = self });
 }
 
 fn handleDestroy(listener: *wl.Listener(*wlr.LayerSurfaceV1), wlr_layer_surface: *wlr.LayerSurfaceV1) void {
diff --git a/river/Subsurface.zig b/river/Subsurface.zig
index 33dd279..0f6f544 100644
--- a/river/Subsurface.zig
+++ b/river/Subsurface.zig
@@ -63,6 +63,11 @@ pub fn create(wlr_subsurface: *wlr.Subsurface, parent: Parent) void {
     wlr_subsurface.events.map.add(&subsurface.map);
     wlr_subsurface.events.unmap.add(&subsurface.unmap);
     wlr_subsurface.surface.events.new_subsurface.add(&subsurface.new_subsurface);
+
+    // There may already be subsurfaces present on this surface that we
+    // aren't aware of and won't receive a new_subsurface event for.
+    var it = wlr_subsurface.surface.subsurfaces.iterator(.forward);
+    while (it.next()) |s| Subsurface.create(s, parent);
 }
 
 fn handleDestroy(listener: *wl.Listener(*wlr.Subsurface), wlr_subsurface: *wlr.Subsurface) void {
diff --git a/river/XdgPopup.zig b/river/XdgPopup.zig
index 0f5b97d..cb7740c 100644
--- a/river/XdgPopup.zig
+++ b/river/XdgPopup.zig
@@ -74,6 +74,11 @@ pub fn create(wlr_xdg_popup: *wlr.XdgPopup, parent: Parent) void {
     wlr_xdg_popup.base.events.unmap.add(&self.unmap);
     wlr_xdg_popup.base.events.new_popup.add(&self.new_popup);
     wlr_xdg_popup.base.surface.events.new_subsurface.add(&self.new_subsurface);
+
+    // There may already be subsurfaces present on this surface that we
+    // aren't aware of and won't receive a new_subsurface event for.
+    var it = wlr_xdg_popup.base.surface.subsurfaces.iterator(.forward);
+    while (it.next()) |s| Subsurface.create(s, parent);
 }
 
 fn handleDestroy(listener: *wl.Listener(*wlr.XdgSurface), wlr_xdg_surface: *wlr.XdgSurface) void {
diff --git a/river/XdgToplevel.zig b/river/XdgToplevel.zig
index 4b597dd..39b2dc1 100644
--- a/river/XdgToplevel.zig
+++ b/river/XdgToplevel.zig
@@ -64,11 +64,16 @@ pub fn init(self: *Self, view: *View, xdg_surface: *wlr.XdgSurface) void {
     xdg_surface.data = @ptrToInt(self);
 
     // Add listeners that are active over the view's entire lifetime
-    self.xdg_surface.events.destroy.add(&self.destroy);
-    self.xdg_surface.events.map.add(&self.map);
-    self.xdg_surface.events.unmap.add(&self.unmap);
-    self.xdg_surface.events.new_popup.add(&self.new_popup);
-    self.xdg_surface.surface.events.new_subsurface.add(&self.new_subsurface);
+    xdg_surface.events.destroy.add(&self.destroy);
+    xdg_surface.events.map.add(&self.map);
+    xdg_surface.events.unmap.add(&self.unmap);
+    xdg_surface.events.new_popup.add(&self.new_popup);
+    xdg_surface.surface.events.new_subsurface.add(&self.new_subsurface);
+
+    // There may already be subsurfaces present on this surface that we
+    // aren't aware of and won't receive a new_subsurface event for.
+    var it = xdg_surface.surface.subsurfaces.iterator(.forward);
+    while (it.next()) |s| Subsurface.create(s, .{ .view = view });
 }
 
 pub fn deinit(self: *Self) void {