diff --git a/src/kiri-mode/cam/client.js b/src/kiri-mode/cam/client.js
index 6a52b451..6bb111a2 100644
--- a/src/kiri-mode/cam/client.js
+++ b/src/kiri-mode/cam/client.js
@@ -509,7 +509,7 @@ CAM.init = function(kiri, api) {
             let clazz = notime ? [ "draggable", "notime" ] : [ "draggable" ];
             let notable = rec.note ? rec.note.split(' ').filter(v => v.charAt(0) === '#') : undefined;
             if (clock) { clazz.push('clock'); title = ` title="end of ops chain\ndrag/drop like an op\nops after this are disabled"` }
-            if (notable?.length) label = notable[0].slice(1);
+            if (notable?.length) label += ` (${notable[0].slice(1)})`;
             html.appendAll([
                 `<div id="${mark+i}" class="${clazz.join(' ')}"${title}>`,
                 `<label class="label">${label}</label>`,
diff --git a/src/kiri-mode/cam/ops.js b/src/kiri-mode/cam/ops.js
index 09cdd6d9..68f144e4 100644
--- a/src/kiri-mode/cam/ops.js
+++ b/src/kiri-mode/cam/ops.js
@@ -963,6 +963,7 @@ class OpTrace extends CamOp {
         }
         // generate tracing offsets from chosen features
         let zTop = workarea.top_z;
+        let zBottom = workarea.bottom_z;
         let sliceOut = this.sliceOut = [];
         let areas = op.areas[widget.id] || [];
         let camTool = new CAM.Tool(settings, tool);
@@ -993,6 +994,9 @@ class OpTrace extends CamOp {
             sliceOut.push(slice);
             return slice;
         }
+        function minZ(z) {
+            return op.bottom && zBottom ? Math.max(zBottom, z - thru) : z - thru;
+        }
         function followZ(poly) {
             if (op.dogbone) {
                 CAM.addDogbones(poly, toolDiam / 5, !op.revbone);
@@ -1119,7 +1123,7 @@ class OpTrace extends CamOp {
                     }
                     for (let pi of POLY.flatten(poly, [], true))
                     if (down) {
-                        let zto = pi.getZ() - thru;
+                        let zto = minZ(pi.getZ());
                         if (zThru && similar(zto,0)) {
                             zto -= zThru;
                         }
@@ -1147,10 +1151,7 @@ class OpTrace extends CamOp {
                 const zbo = widget.track.top - widget.track.box.d;
                 let zmap = {};
                 for (let poly of polys) {
-                    let z = poly.getZ() - thru;
-                    if (op.bottom && camZBottom) {
-                        z = Math.max(z, camZBottom) - zbo;
-                    }
+                    let z = minZ(poly.getZ());
                     if (offover) {
                         let pnew = POLY.offset([poly], -offover, { minArea: 0, open: true });
                         if (pnew) {
diff --git a/src/kiri/ui.js b/src/kiri/ui.js
index d891e810..3678d037 100644
--- a/src/kiri/ui.js
+++ b/src/kiri/ui.js
@@ -132,7 +132,7 @@ gapp.register("kiri.ui", [], (root, exports) => {
             if (Array.isArray(input)) {
                 iid = `confirm-input-${rnd}`;
                 html.append(`<div><textarea rows="15" cols="40" class="grow" type="text" spellcheck="false" id="${iid}"></textarea></div>`);
-            } else if (input) {
+            } else if (input !== undefined) {
                 iid = `confirm-input-${rnd}`;
                 html.append(`<div><input class="grow" type="text" spellcheck="false" id="${iid}"/></div>`);
             }