diff --git a/crates/ui-egui/src/panels/detail.rs b/crates/ui-egui/src/panels/detail.rs
index 36b302106..d4ce522c3 100644
--- a/crates/ui-egui/src/panels/detail.rs
+++ b/crates/ui-egui/src/panels/detail.rs
@@ -258,6 +258,9 @@ pub(crate) fn overlay_supports_window(overlay: lightcraft_pipeline::Overlay) ->
     use lightcraft_pipeline::Overlay as O;
     match overlay {
         O::None | O::Mask { .. } | O::PointColorRange(_) | O::HdrRange | O::Spots(_) => true,
+        // Show All Masks reads every mask's alpha in one GPU readback for the whole frame; not
+        // tested on a window yet, so it keeps the whole-frame render
+        O::AllMasks { .. } => false,
     }
 }