diff --git a/blocks/lists.js b/blocks/lists.js
index 46975d6cd71..dfff7b9f95d 100644
--- a/blocks/lists.js
+++ b/blocks/lists.js
@@ -198,10 +198,13 @@ blocks['lists_create_with'] = {
     let itemBlock = containerBlock.getInputTargetBlock('STACK');
     // Count number of inputs.
     const connections = [];
-    while (itemBlock && !itemBlock.isInsertionMarker()) {
+    while (itemBlock) {
+      if (itemBlock.isInsertionMarker()) {
+        itemBlock = itemBlock.getNextBlock();
+        continue;
+      }
       connections.push(itemBlock.valueConnection_);
-      itemBlock =
-          itemBlock.nextConnection && itemBlock.nextConnection.targetBlock();
+      itemBlock = itemBlock.getNextBlock();
     }
     // Disconnect any children that don't belong.
     for (let i = 0; i < this.itemCount_; i++) {
@@ -226,10 +229,13 @@ blocks['lists_create_with'] = {
     let itemBlock = containerBlock.getInputTargetBlock('STACK');
     let i = 0;
     while (itemBlock) {
+      if (itemBlock.isInsertionMarker()) {
+        itemBlock = itemBlock.getNextBlock();
+        continue;
+      }
       const input = this.getInput('ADD' + i);
       itemBlock.valueConnection_ = input && input.connection.targetConnection;
-      itemBlock =
-          itemBlock.nextConnection && itemBlock.nextConnection.targetBlock();
+      itemBlock = itemBlock.getNextBlock();
       i++;
     }
   },
diff --git a/blocks/logic.js b/blocks/logic.js
index 04e1572beee..9c3ae781e48 100644
--- a/blocks/logic.js
+++ b/blocks/logic.js
@@ -394,7 +394,11 @@ const CONTROLS_IF_MUTATOR_MIXIN = {
     const valueConnections = [null];
     const statementConnections = [null];
     let elseStatementConnection = null;
-    while (clauseBlock && !clauseBlock.isInsertionMarker()) {
+    while (clauseBlock) {
+      if (clauseBlock.isInsertionMarker()) {
+        clauseBlock = clauseBlock.getNextBlock();
+        continue;
+      }
       switch (clauseBlock.type) {
         case 'controls_if_elseif':
           this.elseifCount_++;
@@ -408,8 +412,7 @@ const CONTROLS_IF_MUTATOR_MIXIN = {
         default:
           throw TypeError('Unknown block type: ' + clauseBlock.type);
       }
-      clauseBlock = clauseBlock.nextConnection &&
-          clauseBlock.nextConnection.targetBlock();
+      clauseBlock = clauseBlock.getNextBlock();
     }
     this.updateShape_();
     // Reconnect any child blocks.
@@ -425,6 +428,10 @@ const CONTROLS_IF_MUTATOR_MIXIN = {
     let clauseBlock = containerBlock.nextConnection.targetBlock();
     let i = 1;
     while (clauseBlock) {
+      if (clauseBlock.isInsertionMarker()) {
+        clauseBlock = clauseBlock.getNextBlock();
+        continue;
+      }
       switch (clauseBlock.type) {
         case 'controls_if_elseif': {
           const inputIf = this.getInput('IF' + i);
@@ -445,8 +452,7 @@ const CONTROLS_IF_MUTATOR_MIXIN = {
         default:
           throw TypeError('Unknown block type: ' + clauseBlock.type);
       }
-      clauseBlock = clauseBlock.nextConnection &&
-          clauseBlock.nextConnection.targetBlock();
+      clauseBlock = clauseBlock.getNextBlock();
     }
   },
   /**
diff --git a/blocks/text.js b/blocks/text.js
index efaebb5008e..5c3c2811076 100644
--- a/blocks/text.js
+++ b/blocks/text.js
@@ -781,10 +781,13 @@ const TEXT_JOIN_MUTATOR_MIXIN = {
     let itemBlock = containerBlock.getInputTargetBlock('STACK');
     // Count number of inputs.
     const connections = [];
-    while (itemBlock && !itemBlock.isInsertionMarker()) {
+    while (itemBlock) {
+      if (itemBlock.isInsertionMarker()) {
+        itemBlock = itemBlock.getNextBlock();
+        continue;
+      }
       connections.push(itemBlock.valueConnection_);
-      itemBlock =
-          itemBlock.nextConnection && itemBlock.nextConnection.targetBlock();
+      itemBlock = itemBlock.getNextBlock();
     }
     // Disconnect any children that don't belong.
     for (let i = 0; i < this.itemCount_; i++) {
@@ -809,10 +812,13 @@ const TEXT_JOIN_MUTATOR_MIXIN = {
     let itemBlock = containerBlock.getInputTargetBlock('STACK');
     let i = 0;
     while (itemBlock) {
+      if (itemBlock.isInsertionMarker()) {
+        itemBlock = itemBlock.getNextBlock();
+        continue;
+      }
       const input = this.getInput('ADD' + i);
       itemBlock.valueConnection_ = input && input.connection.targetConnection;
-      itemBlock =
-          itemBlock.nextConnection && itemBlock.nextConnection.targetBlock();
+      itemBlock = itemBlock.getNextBlock();
       i++;
     }
   },