fix: never collapse warning container — always reserve space to prevent layout shift

Replace display:none with persistent visibility:hidden so the warning
area occupies the same vertical space regardless of API result.
This eliminates the layout shift that occurred when the container was
collapsed after the recipient history check returned.

src/popup/index.html

@@ -577,6 +577,19 @@
                     <div id="confirm-fee-amount" class="text-xs"></div>
                 </div>
                 <div id="confirm-warnings" class="mb-2 hidden"></div>
+                <div
+                    id="confirm-recipient-warning"
+                    class="mb-2"
+                    style="visibility: hidden"
+                >
+                    <div
+                        class="border border-red-500 border-dashed p-2 text-xs font-bold text-red-500"
+                    >
+                        WARNING: The recipient address has ZERO transaction
+                        history. This may indicate a fresh or unused address.
+                        Double-check the address before sending.
+                    </div>
+                </div>
                 <div
                     id="confirm-errors"
                     class="mb-2 border border-border border-dashed p-2 hidden"

src/popup/styles/main.css

@@ -15,21 +15,6 @@
     --color-section: #dddddd;
 }
 
-@keyframes copy-flash {
-    0% {
-        background-color: var(--color-fg);
-        color: var(--color-bg);
-    }
-    100% {
-        background-color: transparent;
-        color: inherit;
-    }
-}
-
-.copy-flash {
-    animation: copy-flash 500ms ease-out;
-}
-
 body {
     width: 396px;
     overflow-x: hidden;

src/popup/views/addressDetail.js

@@ -2,7 +2,6 @@ const {
     $,
     showView,
     showFlash,
-    flashCopyElement,
     balanceLinesForAddress,
     addressDotHtml,
     addressTitle,
@@ -238,11 +237,9 @@ function renderTransactions(txs) {
 function init(_ctx) {
     ctx = _ctx;
     $("address-full").addEventListener("click", () => {
-        const el = $("address-full");
-        const addr = el.dataset.full;
+        const addr = $("address-full").dataset.full;
         if (addr) {
             navigator.clipboard.writeText(addr);
-            flashCopyElement(el);
             showFlash("Copied!");
         }
     });
@@ -357,21 +354,17 @@ function init(_ctx) {
     });
 
     $("export-privkey-value").addEventListener("click", () => {
-        const el = $("export-privkey-value");
-        const key = el.textContent;
+        const key = $("export-privkey-value").textContent;
         if (key) {
             navigator.clipboard.writeText(key);
-            flashCopyElement(el);
             showFlash("Copied!");
         }
     });
 
     $("export-privkey-address").addEventListener("click", () => {
-        const el = $("export-privkey-address");
-        const full = el.dataset.full;
+        const full = $("export-privkey-address").dataset.full;
         if (full) {
             navigator.clipboard.writeText(full);
-            flashCopyElement(el);
             showFlash("Copied!");
         }
     });

src/popup/views/addressToken.js

@@ -5,7 +5,6 @@ const {
     $,
     showView,
     showFlash,
-    flashCopyElement,
     addressDotHtml,
     addressTitle,
     escapeHtml,
@@ -314,11 +313,9 @@ function renderTransactions(txs) {
 function init(_ctx) {
     ctx = _ctx;
     $("address-token-full").addEventListener("click", () => {
-        const el = $("address-token-full");
-        const addr = el.dataset.full;
+        const addr = $("address-token-full").dataset.full;
         if (addr) {
             navigator.clipboard.writeText(addr);
-            flashCopyElement(el);
             showFlash("Copied!");
         }
     });
@@ -327,7 +324,6 @@ function init(_ctx) {
         const copyEl = e.target.closest("[data-copy]");
         if (copyEl) {
             navigator.clipboard.writeText(copyEl.dataset.copy);
-            flashCopyElement(copyEl);
             showFlash("Copied!");
         }
     });
@@ -376,7 +372,6 @@ function init(_ctx) {
         if (copyEl) {
             copyEl.addEventListener("click", () => {
                 navigator.clipboard.writeText(copyEl.dataset.copy);
-                flashCopyElement(copyEl);
                 showFlash("Copied!");
             });
         }

src/popup/views/confirmTx.js

@@ -15,7 +15,6 @@ const {
     hideError,
     showView,
     showFlash,
-    flashCopyElement,
     addressTitle,
     addressDotHtml,
     escapeHtml,
@@ -117,7 +116,6 @@ function show(txInfo) {
         if (copyEl) {
             copyEl.onclick = () => {
                 navigator.clipboard.writeText(copyEl.dataset.copy);
-                flashCopyElement(copyEl);
                 showFlash("Copied!");
             };
         }
@@ -245,7 +243,13 @@ function show(txInfo) {
     state.viewData = { pendingTx: txInfo };
     showView("confirm-tx");
 
+    // Reset recipient warning: reserve space (visibility:hidden) while
+    // the async check runs, preventing layout shift per README policy.
+    const recipientWarning = $("confirm-recipient-warning");
+    recipientWarning.style.visibility = "hidden";
+
     estimateGas(txInfo);
+    checkRecipientHistory(txInfo);
 }
 
 async function estimateGas(txInfo) {
@@ -288,6 +292,30 @@ async function estimateGas(txInfo) {
     }
 }
 
+async function checkRecipientHistory(txInfo) {
+    const el = $("confirm-recipient-warning");
+    try {
+        const provider = getProvider(state.rpcUrl);
+        // Skip warning for contract addresses — they may legitimately
+        // have zero outgoing transactions (getTransactionCount returns
+        // the nonce, i.e. sent-tx count only).
+        const code = await provider.getCode(txInfo.to);
+        if (code && code !== "0x") {
+            // Contract address — no warning needed, keep space reserved
+            // but invisible to prevent layout shift
+            return;
+        }
+        const txCount = await provider.getTransactionCount(txInfo.to);
+        if (txCount === 0) {
+            el.style.visibility = "visible";
+        }
+        // If txCount > 0, leave visibility:hidden — space stays reserved
+    } catch (e) {
+        log.errorf("recipient history check failed:", e.message);
+        // On error, leave visibility:hidden — no layout shift, no false warning
+    }
+}
+
 function init(ctx) {
     $("btn-confirm-send").addEventListener("click", async () => {
         const password = $("confirm-tx-password").value;

src/popup/views/helpers.js

@@ -76,18 +76,6 @@ function clearFlash() {
     $("flash-msg").textContent = "";
 }
 
-function flashCopyElement(el) {
-    el.classList.remove("copy-flash");
-    // Force reflow so re-adding the class restarts the animation.
-    void el.offsetWidth;
-    el.classList.add("copy-flash");
-    el.addEventListener(
-        "animationend",
-        () => el.classList.remove("copy-flash"),
-        { once: true },
-    );
-}
-
 function showFlash(msg, duration = 2000) {
     clearFlash();
     $("flash-msg").textContent = msg;
@@ -277,7 +265,6 @@ module.exports = {
     hideError,
     showView,
     showFlash,
-    flashCopyElement,
     balanceLine,
     balanceLinesForAddress,
     addressColor,

src/popup/views/home.js

@@ -2,7 +2,6 @@ const {
     $,
     showView,
     showFlash,
-    flashCopyElement,
     balanceLinesForAddress,
     isoDate,
     timeAgo,
@@ -86,9 +85,8 @@ function renderActiveAddress() {
         el.innerHTML =
             `<span class="underline decoration-dashed cursor-pointer" id="active-addr-copy">${dot}${escapeHtml(addr)}</span>` +
             `<a href="${link}" target="_blank" rel="noopener" class="inline-flex items-center">${EXT_ICON}</a>`;
-        $("active-addr-copy").addEventListener("click", (e) => {
+        $("active-addr-copy").addEventListener("click", () => {
             navigator.clipboard.writeText(addr);
-            flashCopyElement(e.currentTarget);
             showFlash("Copied!");
         });
     } else {

src/popup/views/receive.js

@@ -2,7 +2,6 @@ const {
     $,
     showView,
     showFlash,
-    flashCopyElement,
     formatAddressHtml,
     addressTitle,
 } = require("./helpers");
@@ -62,21 +61,17 @@ function show() {
 
 function init(ctx) {
     $("receive-address-block").addEventListener("click", () => {
-        const el = $("receive-address-block");
-        const addr = el.dataset.full;
+        const addr = $("receive-address-block").dataset.full;
         if (addr) {
             navigator.clipboard.writeText(addr);
-            flashCopyElement(el);
             showFlash("Copied!");
         }
     });
 
     $("btn-receive-copy").addEventListener("click", () => {
-        const block = $("receive-address-block");
-        const addr = block.dataset.full;
+        const addr = $("receive-address-block").dataset.full;
         if (addr) {
             navigator.clipboard.writeText(addr);
-            flashCopyElement(block);
             showFlash("Copied!");
         }
     });

src/popup/views/transactionDetail.js

@@ -5,7 +5,6 @@ const {
     $,
     showView,
     showFlash,
-    flashCopyElement,
     addressDotHtml,
     addressTitle,
     escapeHtml,
@@ -171,7 +170,6 @@ function render() {
         .forEach((el) => {
             el.onclick = () => {
                 navigator.clipboard.writeText(el.dataset.copy);
-                flashCopyElement(el);
                 showFlash("Copied!");
             };
         });
@@ -249,7 +247,6 @@ async function loadCalldata(txHash, toAddress) {
             container.querySelectorAll("[data-copy]").forEach((el) => {
                 el.onclick = () => {
                     navigator.clipboard.writeText(el.dataset.copy);
-                    flashCopyElement(el);
                     showFlash("Copied!");
                 };
             });

src/popup/views/txStatus.js

@@ -4,7 +4,6 @@ const {
     $,
     showView,
     showFlash,
-    flashCopyElement,
     addressDotHtml,
     addressTitle,
     escapeHtml,
@@ -77,7 +76,6 @@ function attachCopyHandlers(viewId) {
         .forEach((el) => {
             el.onclick = () => {
                 navigator.clipboard.writeText(el.dataset.copy);
-                flashCopyElement(el);
                 showFlash("Copied!");
             };
         });