diff --git a/InvenTree/build/serializers.py b/InvenTree/build/serializers.py
index 8f76f3e603..a18f58fb76 100644
--- a/InvenTree/build/serializers.py
+++ b/InvenTree/build/serializers.py
@@ -309,6 +309,8 @@ class BuildAllocationItemSerializer(serializers.Serializer):
 
     def validate_bom_item(self, bom_item):
         
+        # TODO: Fix this validation - allow for variants and substitutes!
+
         build = self.context['build']
 
         # BomItem must point to the same 'part' as the parent build
diff --git a/InvenTree/build/templates/build/detail.html b/InvenTree/build/templates/build/detail.html
index 908a7dfa4a..f87eec90a0 100644
--- a/InvenTree/build/templates/build/detail.html
+++ b/InvenTree/build/templates/build/detail.html
@@ -523,6 +523,10 @@ $('#allocate-selected-items').click(function() {
 
     var bom_items = $("#allocation-table-untracked").bootstrapTable("getSelections");
 
+    if (bom_items.length == 0) {
+        bom_items = $("#allocation-table-untracked").bootstrapTable('getData');
+    }
+
     allocateStockToBuild(
         {{ build.pk }},
         {{ build.part.pk }},
diff --git a/InvenTree/templates/js/translated/build.js b/InvenTree/templates/js/translated/build.js
index 0c291dd8da..b6c98fc49e 100644
--- a/InvenTree/templates/js/translated/build.js
+++ b/InvenTree/templates/js/translated/build.js
@@ -1404,6 +1404,24 @@ function allocateStockToBuild(build_id, part_id, bom_items, options={}) {
                         render_part_detail: true,
                         render_location_detail: true,
                         auto_fill: true,
+                        onSelect: function(data, field, opts) {
+                            // Adjust the 'quantity' field based on availability
+
+                            if (!('quantity' in data)) {
+                                return;
+                            }
+
+                            // Quantity remaining to be allocated
+                            var remaining = Math.max((bom_item.required || 0) - (bom_item.allocated || 0), 0);
+
+                            // Calculate the available quantity
+                            var available = Math.max((data.quantity || 0) - (data.allocated || 0), 0);
+
+                            // Maximum amount that we need
+                            var desired = Math.min(available, remaining);
+
+                            updateFieldValue(`items_quantity_${bom_item.pk}`, desired, {}, opts);
+                        },
                         adjustFilters: function(filters) {
                             // Restrict query to the selected location
                             var location = getFormFieldValue(
diff --git a/InvenTree/templates/js/translated/forms.js b/InvenTree/templates/js/translated/forms.js
index 1bfe196286..db2c8e46cc 100644
--- a/InvenTree/templates/js/translated/forms.js
+++ b/InvenTree/templates/js/translated/forms.js
@@ -1426,6 +1426,11 @@ function initializeRelatedField(field, fields, options) {
                 data = item.element.instance;
             }
 
+            // Run optional callback function
+            if (field.onSelect && data) {
+                field.onSelect(data, field, options);
+            }
+
             if (!data.pk) {
                 return field.placeholder || '';
             }
diff --git a/InvenTree/templates/js/translated/order.js b/InvenTree/templates/js/translated/order.js
index 7cadfe453d..67fef0b853 100644
--- a/InvenTree/templates/js/translated/order.js
+++ b/InvenTree/templates/js/translated/order.js
@@ -1641,6 +1641,13 @@ function loadSalesOrderLineItemTable(table, options={}) {
 
             var line_item = $(table).bootstrapTable('getRowByUniqueId', pk);
 
+            // Quantity remaining to be allocated
+            var remaining = (line_item.quantity || 0) - (line_item.allocated || 0);
+
+            if (remaining < 0) {
+                remaining = 0;
+            }
+
             var fields = {
                 // SalesOrderLineItem reference
                 line: {
@@ -1654,9 +1661,26 @@ function loadSalesOrderLineItemTable(table, options={}) {
                         in_stock: true,
                         part: line_item.part,
                         exclude_so_allocation: options.order,
-                    } 
+                    },
+                    auto_fill: true,
+                    onSelect: function(data, field, opts) {
+                        // Quantity available from this stock item
+
+                        if (!('quantity' in data)) {
+                            return;
+                        }
+
+                        // Calculate the available quantity
+                        var available = Math.max((data.quantity || 0) - (data.allocated || 0), 0);
+
+                        // Maximum amount that we need
+                        var desired = Math.min(available, remaining);
+
+                        updateFieldValue('quantity', desired, {}, opts);
+                    }
                 },
                 quantity: {
+                    value: remaining,
                 },
             };
 
@@ -1752,7 +1776,7 @@ function loadSalesOrderLineItemTable(table, options={}) {
         showFooter: true,
         uniqueId: 'pk',
         detailView: show_detail,
-        detailViewByClick: show_detail,
+        detailViewByClick: false,
         detailFilter: function(index, row) {
             if (pending) {
                 // Order is pending