fix: reserve space for all error/status messages — closes #123

Replace display:none (hidden class) with visibility:hidden/visible for all
error, warning, and status message elements across the extension UI. This
prevents layout shift when messages appear or disappear.

Changes:
- helpers.js: showError/hideError now use visibility instead of hidden class
- index.html: all error/status divs use visibility:hidden + min-height
- confirmTx.js: warnings, errors, fee section use visibility
- approval.js: tx-error, sign-error, danger-warning use visibility
- addressDetail.js: export-privkey-flash uses visibility
- deleteWallet.js: delete-wallet-flash uses visibility
- addWallet.js: phrase-warning uses visibility
- receive.js: erc20-warning uses visibility
- addToken.js: add-token-info uses visibility
- settingsAddToken.js: settings-addtoken-info uses visibility

src/popup/index.html

@@ -107,7 +107,8 @@
                     </div>
                     <div
                         id="add-wallet-phrase-warning"
-                        class="text-xs mb-2 border border-border border-dashed p-2 hidden"
+                        class="text-xs mb-2 border border-border border-dashed p-2"
+                        style="visibility: hidden"
                     >
                         Write these words down and keep them safe. Anyone with
                         them can take your funds; if you lose them, your wallet
@@ -375,7 +376,8 @@
                 </p>
                 <div
                     id="export-privkey-flash"
-                    class="text-xs mb-2 hidden"
+                    class="text-xs mb-2 min-h-[1.25rem]"
+                    style="visibility: hidden"
                 ></div>
                 <div id="export-privkey-password-section" class="mb-2">
                     <label class="block mb-1">Password</label>
@@ -579,13 +581,17 @@
                     <div class="text-xs text-muted mb-1">Your balance</div>
                     <div id="confirm-balance" class="text-xs"></div>
                 </div>
-                <div id="confirm-fee" class="mb-3 hidden">
+                <div id="confirm-fee" class="mb-3" style="visibility: hidden">
                     <div class="text-xs text-muted mb-1">
                         Estimated network fee
                     </div>
                     <div id="confirm-fee-amount" class="text-xs"></div>
                 </div>
-                <div id="confirm-warnings" class="mb-2 hidden"></div>
+                <div
+                    id="confirm-warnings"
+                    class="mb-2"
+                    style="visibility: hidden"
+                ></div>
                 <div
                     id="confirm-recipient-warning"
                     class="mb-2"
@@ -601,7 +607,8 @@
                 </div>
                 <div
                     id="confirm-errors"
-                    class="mb-2 border border-border border-dashed p-2 hidden"
+                    class="mb-2 border border-border border-dashed p-2"
+                    style="visibility: hidden; min-height: 1.25rem"
                 ></div>
                 <div class="mb-2">
                     <label class="block mb-1 text-xs">Password</label>
@@ -614,6 +621,7 @@
                 <div
                     id="confirm-tx-password-error"
                     class="text-xs mb-2 min-h-[1.25rem]"
+                    style="visibility: hidden"
                 ></div>
                 <button
                     id="btn-confirm-send"
@@ -728,7 +736,8 @@
                 </button>
                 <div
                     id="receive-erc20-warning"
-                    class="text-xs border border-border border-dashed p-2 mt-3 hidden"
+                    class="text-xs border border-border border-dashed p-2 mt-3"
+                    style="visibility: hidden"
                 ></div>
             </div>
 
@@ -756,7 +765,8 @@
                 </div>
                 <div
                     id="add-token-info"
-                    class="text-xs text-muted mb-2 hidden"
+                    class="text-xs text-muted mb-2 min-h-[1.25rem]"
+                    style="visibility: hidden"
                 ></div>
                 <div class="mb-2">
                     <label class="block mb-1 text-xs text-muted"
@@ -938,7 +948,8 @@
                 </p>
                 <div
                     id="delete-wallet-flash"
-                    class="text-xs text-red-500 mb-2 hidden"
+                    class="text-xs text-red-500 mb-2 min-h-[1.25rem]"
+                    style="visibility: hidden"
                 ></div>
                 <div class="mb-2">
                     <label class="block mb-1">Password</label>
@@ -1013,7 +1024,8 @@
                     />
                     <div
                         id="settings-addtoken-info"
-                        class="text-xs text-muted mt-1 hidden"
+                        class="text-xs text-muted mt-1 min-h-[1.25rem]"
+                        style="visibility: hidden"
                     ></div>
                     <button
                         id="btn-settings-addtoken-manual"
@@ -1139,7 +1151,8 @@
                 </div>
                 <div
                     id="approve-tx-error"
-                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem] hidden"
+                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem]"
+                    style="visibility: hidden"
                 ></div>
                 <div class="flex justify-between">
                     <button
@@ -1167,8 +1180,10 @@
 
                 <div
                     id="approve-sign-danger-warning"
-                    class="hidden mb-3 p-2 text-xs font-bold"
+                    class="mb-3 p-2 text-xs font-bold"
                     style="
+                        visibility: hidden;
+                        min-height: 1.25rem;
                         background: #fee2e2;
                         color: #991b1b;
                         border: 2px solid #dc2626;
@@ -1205,7 +1220,8 @@
                 </div>
                 <div
                     id="approve-sign-error"
-                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem] hidden"
+                    class="text-xs mb-2 border border-border border-dashed p-1 min-h-[1.25rem]"
+                    style="visibility: hidden"
                 ></div>
                 <div class="flex justify-between">
                     <button

src/popup/views/addToken.js

@@ -7,7 +7,8 @@ const { log } = require("../../shared/log");
 
 function show() {
     $("add-token-address").value = "";
-    $("add-token-info").classList.add("hidden");
+    $("add-token-info").textContent = "";
+    $("add-token-info").style.visibility = "hidden";
     const list = $("common-token-list");
     list.innerHTML = getTopTokens(25)
         .map(
@@ -45,7 +46,7 @@ function init(ctx) {
         }
         const infoEl = $("add-token-info");
         infoEl.textContent = "Looking up token...";
-        infoEl.classList.remove("hidden");
+        infoEl.style.visibility = "visible";
         log.debugf("Looking up token contract", contractAddr);
         try {
             const info = await lookupTokenInfo(contractAddr, state.rpcUrl);
@@ -63,7 +64,8 @@ function init(ctx) {
             const detail = e.shortMessage || e.message || String(e);
             log.errorf("Token lookup failed for", contractAddr, detail);
             showFlash(detail);
-            infoEl.classList.add("hidden");
+            infoEl.textContent = "";
+            infoEl.style.visibility = "hidden";
         }
     });
 

src/popup/views/addWallet.js

@@ -71,7 +71,7 @@ function show() {
     $("import-xprv-key").value = "";
     $("add-wallet-password").value = "";
     $("add-wallet-password-confirm").value = "";
-    $("add-wallet-phrase-warning").classList.add("hidden");
+    $("add-wallet-phrase-warning").style.visibility = "hidden";
     switchMode("mnemonic");
     showView("add-wallet");
 }
@@ -281,7 +281,7 @@ function init(ctx) {
     // Generate mnemonic
     $("btn-generate-phrase").addEventListener("click", () => {
         $("wallet-mnemonic").value = generateMnemonic();
-        $("add-wallet-phrase-warning").classList.remove("hidden");
+        $("add-wallet-phrase-warning").style.visibility = "visible";
     });
 
     // Import / confirm

src/popup/views/addressDetail.js

@@ -312,8 +312,8 @@ function init(_ctx) {
         $("export-privkey-address").textContent = addr.address;
         $("export-privkey-address").dataset.full = addr.address;
         $("export-privkey-password").value = "";
-        $("export-privkey-flash").classList.add("hidden");
         $("export-privkey-flash").textContent = "";
+        $("export-privkey-flash").style.visibility = "hidden";
         $("export-privkey-password-section").classList.remove("hidden");
         $("export-privkey-result").classList.add("hidden");
         $("export-privkey-value").textContent = "";
@@ -324,7 +324,7 @@ function init(_ctx) {
         const password = $("export-privkey-password").value;
         if (!password) {
             $("export-privkey-flash").textContent = "Password is required.";
-            $("export-privkey-flash").classList.remove("hidden");
+            $("export-privkey-flash").style.visibility = "visible";
             return;
         }
         const btn = $("btn-export-privkey-confirm");
@@ -345,10 +345,10 @@ function init(_ctx) {
             $("export-privkey-password-section").classList.add("hidden");
             $("export-privkey-value").textContent = privateKey;
             $("export-privkey-result").classList.remove("hidden");
-            $("export-privkey-flash").classList.add("hidden");
+            $("export-privkey-flash").style.visibility = "hidden";
         } catch {
             $("export-privkey-flash").textContent = "Wrong password.";
-            $("export-privkey-flash").classList.remove("hidden");
+            $("export-privkey-flash").style.visibility = "visible";
         } finally {
             btn.disabled = false;
             btn.classList.remove("text-muted");

src/popup/views/approval.js

@@ -269,7 +269,7 @@ function showTxApproval(details) {
     }
 
     $("approve-tx-password").value = "";
-    $("approve-tx-error").classList.add("hidden");
+    hideError("approve-tx-error");
 
     showView("approve-tx");
 }
@@ -351,10 +351,10 @@ function showSignApproval(details) {
     if (warningEl) {
         if (sp.dangerWarning) {
             warningEl.textContent = sp.dangerWarning;
-            warningEl.classList.remove("hidden");
+            warningEl.style.visibility = "visible";
         } else {
             warningEl.textContent = "";
-            warningEl.classList.add("hidden");
+            warningEl.style.visibility = "hidden";
         }
     }
 

src/popup/views/confirmTx.js

@@ -186,9 +186,10 @@ function show(txInfo) {
                     `<div class="border border-border border-dashed p-2 mb-1 text-xs font-bold">WARNING: ${w}</div>`,
             )
             .join("");
-        warningsEl.classList.remove("hidden");
+        warningsEl.style.visibility = "visible";
     } else {
-        warningsEl.classList.add("hidden");
+        warningsEl.innerHTML = "";
+        warningsEl.style.visibility = "hidden";
     }
 
     // Check for errors
@@ -226,11 +227,12 @@ function show(txInfo) {
         errorsEl.innerHTML = errors
             .map((e) => `<div class="text-xs">${e}</div>`)
             .join("");
-        errorsEl.classList.remove("hidden");
+        errorsEl.style.visibility = "visible";
         sendBtn.disabled = true;
         sendBtn.classList.add("text-muted");
     } else {
-        errorsEl.classList.add("hidden");
+        errorsEl.innerHTML = "";
+        errorsEl.style.visibility = "hidden";
         sendBtn.disabled = false;
         sendBtn.classList.remove("text-muted");
     }
@@ -240,7 +242,7 @@ function show(txInfo) {
     hideError("confirm-tx-password-error");
 
     // Gas estimate — show placeholder then fetch async
-    $("confirm-fee").classList.remove("hidden");
+    $("confirm-fee").style.visibility = "visible";
     $("confirm-fee-amount").textContent = "Estimating...";
     state.viewData = { pendingTx: txInfo };
     showView("confirm-tx");

src/popup/views/deleteWallet.js

@@ -12,7 +12,7 @@ function show(walletIdx) {
         wallet.name || "Wallet " + (walletIdx + 1);
     $("delete-wallet-password").value = "";
     $("delete-wallet-flash").textContent = "";
-    $("delete-wallet-flash").classList.add("hidden");
+    $("delete-wallet-flash").style.visibility = "hidden";
     showView("delete-wallet-confirm");
 }
 
@@ -29,14 +29,14 @@ function init(_ctx) {
         if (!pw) {
             $("delete-wallet-flash").textContent =
                 "Please enter your password.";
-            $("delete-wallet-flash").classList.remove("hidden");
+            $("delete-wallet-flash").style.visibility = "visible";
             return;
         }
 
         if (deleteWalletIndex === null) {
             $("delete-wallet-flash").textContent =
                 "No wallet selected for deletion.";
-            $("delete-wallet-flash").classList.remove("hidden");
+            $("delete-wallet-flash").style.visibility = "visible";
             return;
         }
 
@@ -52,7 +52,7 @@ function init(_ctx) {
             await decryptWithPassword(wallet.encryptedSecret, pw);
         } catch (_e) {
             $("delete-wallet-flash").textContent = "Wrong password.";
-            $("delete-wallet-flash").classList.remove("hidden");
+            $("delete-wallet-flash").style.visibility = "visible";
             btn.disabled = false;
             btn.classList.remove("text-muted");
             return;

src/popup/views/helpers.js

@@ -40,11 +40,13 @@ function $(id) {
 function showError(id, msg) {
     const el = $(id);
     el.textContent = msg;
-    el.classList.remove("hidden");
+    el.style.visibility = "visible";
 }
 
 function hideError(id) {
-    $(id).classList.add("hidden");
+    const el = $(id);
+    el.textContent = "";
+    el.style.visibility = "hidden";
 }
 
 function showView(name) {

src/popup/views/receive.js

@@ -53,9 +53,10 @@ function show() {
             "This is an ERC-20 token. Only send " +
             symbol +
             " on the Ethereum network to this address. Sending tokens on other networks will result in permanent loss.";
-        warningEl.classList.remove("hidden");
+        warningEl.style.visibility = "visible";
     } else {
-        warningEl.classList.add("hidden");
+        warningEl.textContent = "";
+        warningEl.style.visibility = "hidden";
     }
     showView("receive");
 }

src/popup/views/settingsAddToken.js

@@ -73,7 +73,8 @@ function renderDropdown() {
 
 function show() {
     $("settings-addtoken-address").value = "";
-    $("settings-addtoken-info").classList.add("hidden");
+    $("settings-addtoken-info").textContent = "";
+    $("settings-addtoken-info").style.visibility = "hidden";
     renderTop10();
     renderDropdown();
     showView("settings-addtoken");
@@ -129,7 +130,7 @@ function init(_ctx) {
         }
         const infoEl = $("settings-addtoken-info");
         infoEl.textContent = "Looking up token...";
-        infoEl.classList.remove("hidden");
+        infoEl.style.visibility = "visible";
         log.debugf("Looking up token contract", addr);
         try {
             const info = await lookupTokenInfo(addr, state.rpcUrl);
@@ -143,7 +144,8 @@ function init(_ctx) {
             await saveState();
             showFlash("Added " + info.symbol);
             $("settings-addtoken-address").value = "";
-            infoEl.classList.add("hidden");
+            infoEl.textContent = "";
+            infoEl.style.visibility = "hidden";
             renderTop10();
             renderDropdown();
             ctx.doRefreshAndRender();
@@ -151,7 +153,8 @@ function init(_ctx) {
             const detail = e.shortMessage || e.message || String(e);
             log.errorf("Token lookup failed for", addr, detail);
             showFlash(detail);
-            infoEl.classList.add("hidden");
+            infoEl.textContent = "";
+            infoEl.style.visibility = "hidden";
         }
     });
 }