diff --git a/src/app/control/actions.rs b/src/app/control/actions.rs
index 923f1d775..c169d5f4a 100644
--- a/src/app/control/actions.rs
+++ b/src/app/control/actions.rs
@@ -1166,6 +1166,8 @@ impl OpenCADStudio {
         let name = string(req, "name")?;
         let msg = match name {
             "close_modal" => Message::CloseModal,
+            // Show a layout (or "Model"), as clicking its tab does.
+            "layout_switch" => Message::LayoutSwitch(string(req, "value")?.into()),
             // The "changed outside" modal's suggested actions (D6): reload
             // the disk copy, keep the in-memory one and overwrite, save as,
             // or dismiss. Native only — the web build has no such dialog.
diff --git a/src/scene/mod.rs b/src/scene/mod.rs
index f2d821ccf..fa56c3c69 100644
--- a/src/scene/mod.rs
+++ b/src/scene/mod.rs
@@ -7223,12 +7223,20 @@ impl Scene {
         if block == self.model_space_block_handle() {
             *self.model_wire_gpu_patch.borrow_mut() = None;
         }
+        // Every content viewport of the shown layout holds a set of its own;
+        // a cap below their count cleared them all each frame and rebuilt
+        // every viewport's wires on every redraw (#1769).
+        let shown = if self.current_layout == "Model" {
+            0
+        } else {
+            self.paper_viewport_handles().2.len()
+        };
         let mut sets = self.resident_wire_sets.borrow_mut();
         // Evict stale entries (older epochs / abandoned keys) so switching
         // spaces or re-scaling a viewport can't accumulate dead full sets.
         let cur_epoch = self.geometry_epoch;
         sets.retain(|_, set| set.epoch == cur_epoch);
-        if sets.len() > 16 {
+        if sets.len() > 16.max(shown + 2) {
             sets.clear();
         }
         sets.insert(