diff --git a/generic/forms.py b/generic/forms.py
index 34ea0f73..20d81691 100755
--- a/generic/forms.py
+++ b/generic/forms.py
@@ -78,6 +78,9 @@ from crispy_forms.bootstrap import Accordion, AccordionGroup
 
 from dal import autocomplete
 from autocomplete import widgets as htmx_widgets, Autocomplete, AutocompleteWidget, ModelAutocomplete, register as autocomplete_register
+from django.utils.safestring import mark_safe
+from django.urls import reverse
+from django.contrib.auth.models import User
 
 
 class SplitDateTimeFieldDefaultTime(SplitDateTimeField):
@@ -554,12 +557,186 @@ class UserUserGroupModelChoiceField(ModelMultipleChoiceField):
 
 
 class UserUserGroupForm(ModelForm):
+    class UserSearchSelectMultiple(object):
+        """
+        Lightweight widget renderer for a searchable multi-user selector.
+        Renders a hidden <select multiple> containing selected user ids and
+        a search box with results. Uses a small inline script to fetch
+        results from the `generic:user_search_widget` endpoint and add/remove
+        users from the selection.
+        This keeps implementation simple and avoids external JS dependencies.
+        """
+
+        def __init__(self, name, value):
+            self.name = name
+            # value is a list of selected user ids
+            self.value = value or []
+
+        def render(self):
+            field_id = f"id_{self.name}"
+            search_id = f"user_search_{self.name}"
+            results_id = f"user_search_results_{self.name}"
+            selected_list_id = f"selected_users_{self.name}"
+
+            # Build initial options for selected users
+            users = User.objects.filter(pk__in=self.value) if self.value else []
+            options_html = ""
+            selected_html = ""
+            for u in users:
+                options_html += f'<option value="{u.pk}" selected>{u.get_full_name() or u.username} - {u.email}</option>'
+                selected_html += (
+                    f'<li id="selected_user_{self.name}_{u.pk}" class="list-group-item d-flex justify-content-between align-items-center">'
+                    f'<span>{u.get_full_name() or u.username} <small class="text-muted">{u.email}</small></span>'
+                    f'<button type="button" class="btn btn-sm btn-outline-danger ms-2" onclick="removeUserFromField(\'{self.name}\', {u.pk})">Remove</button>'
+                    f'</li>'
+                )
+
+            url = reverse("generic:user_search_widget")
+
+            html = f"""
+<div class="user-search-widget">
+  <select name="{self.name}" id="{field_id}" multiple class="d-none">
+    {options_html}
+  </select>
+
+  <div class="mb-2">
+    <input type="search" id="{search_id}" class="form-control form-control-sm" placeholder="Search users by name, username or email" />
+    <div id="{results_id}" class="mt-2"></div>
+  </div>
+
+  <div>
+    <label class="form-label small">Selected users</label>
+    <ul id="{selected_list_id}" class="list-group list-group-flush">
+      {selected_html}
+    </ul>
+  </div>
+
+  <script>
+    (function() {{
+      const search = document.getElementById('{search_id}');
+      const results = document.getElementById('{results_id}');
+      const select = document.getElementById('{field_id}');
+      const selectedList = document.getElementById('{selected_list_id}');
+
+      let timeout = null;
+      function fetchResults(q) {{
+        if (!q || q.trim().length === 0) {{
+          results.innerHTML = '';
+          return;
+        }}
+        fetch('{url}?field=' + encodeURIComponent('{self.name}') + '&q=' + encodeURIComponent(q))
+          .then(r => r.text())
+          .then(html => {{ results.innerHTML = html; }});
+      }}
+
+      search.addEventListener('keyup', function(e) {{
+        clearTimeout(timeout);
+        timeout = setTimeout(() => fetchResults(search.value), 300);
+      }});
+
+      window.addUserToField = function(fieldName, id, text) {{
+        const sel = document.getElementById('id_' + fieldName);
+        if (!sel) return;
+        // prevent duplicate
+        for (let i=0;i<sel.options.length;i++) {{ if (sel.options[i].value == id) return; }}
+        const opt = document.createElement('option'); opt.value = id; opt.selected = true; opt.text = text;
+        sel.appendChild(opt);
+
+        // add to visible list
+        const li = document.createElement('li');
+        li.className = 'list-group-item d-flex justify-content-between align-items-center';
+        li.id = 'selected_user_' + fieldName + '_' + id;
+        const span = document.createElement('span'); span.innerHTML = text;
+        const btn = document.createElement('button'); btn.type = 'button'; btn.className = 'btn btn-sm btn-outline-danger ms-2'; btn.innerText = 'Remove';
+        btn.addEventListener('click', function() {{ removeUserFromField(fieldName, id); }});
+        li.appendChild(span); li.appendChild(btn);
+        selectedList.appendChild(li);
+      }}
+
+      window.removeUserFromField = function(fieldName, id) {{
+        const sel = document.getElementById('id_' + fieldName);
+        if (!sel) return;
+        for (let i=sel.options.length-1;i>=0;i--) {{ if (sel.options[i].value == id) sel.remove(i); }}
+        const li = document.getElementById('selected_user_' + fieldName + '_' + id);
+        if (li && li.parentNode) li.parentNode.removeChild(li);
+      }}
+    }})();
+  </script>
+</div>
+"""
+
+            return mark_safe(html)
+
     users = UserUserGroupModelChoiceField(
         required=False,
         queryset=User.objects.all(),
-        widget=FilteredSelectMultiple(verbose_name="Users", is_stacked=False),
+        # use our lightweight widget rendering
+        widget=None,
     )
 
+    # monkey-patch the field's widget rendering when the form is instantiated
+    def __init__(self, *args, **kwargs):
+        ModelForm.__init__(self, *args, **kwargs)
+        # replace widget with callable that renders our HTML
+        if 'users' in self.fields:
+            orig_field = self.fields['users']
+
+            class RenderWrapper:
+                def __init__(self, field):
+                    self.field = field
+
+                # Minimal widget-compatible wrapper used by Django templates and
+                # form machinery. We implement the small subset of the Widget
+                # API that the templates/checks expect: `is_hidden`,
+                # `needs_multipart_form`, `render(...)` and `value_from_datadict(...)`.
+                is_hidden = False
+                needs_multipart_form = False
+                use_fieldset = False
+                # attrs is expected by BoundField.id_for_label (widget.attrs.get('id'))
+                attrs = {}
+
+                def render(self, name, value, attrs=None, renderer=None):
+                    # store attrs so template helpers can inspect them
+                    self.attrs = attrs or {}
+                    value = value or []
+                    widget = UserUserGroupForm.UserSearchSelectMultiple(name, value)
+                    return widget.render()
+
+                def value_from_datadict(self, data, files, name):
+                    # data is usually QueryDict with getlist
+                    if hasattr(data, 'getlist'):
+                        return data.getlist(name)
+                    # fallback
+                    val = data.get(name)
+                    if val is None:
+                        return []
+                    return [val]
+
+                def id_for_label(self, id_):
+                    # Called by BoundField.id_for_label; prefer explicit id in attrs
+                    try:
+                        if hasattr(self, 'attrs') and self.attrs and self.attrs.get('id'):
+                            return self.attrs.get('id')
+                    except Exception:
+                        pass
+                    return id_
+
+                def use_required_attribute(self, initial):
+                    # Called by Django to decide whether to add the required HTML attribute.
+                    # We defer to the underlying field/widget if available; otherwise
+                    # return False to avoid unexpected 'required' attributes.
+                    try:
+                        if hasattr(self, 'field') and getattr(self, 'field') is not None:
+                            # If original field/widget had such method, prefer it.
+                            orig_widget = getattr(self.field, 'widget', None)
+                            if orig_widget and hasattr(orig_widget, 'use_required_attribute'):
+                                return orig_widget.use_required_attribute(initial)
+                    except Exception:
+                        pass
+                    return False
+
+            self.fields['users'].widget = RenderWrapper(orig_field)
+
     class Meta:
         model = UserUserGroup
         fields = ["name", "archive", "open_access", "users"]
diff --git a/generic/models.py b/generic/models.py
index 49b6b20e..c69d8740 100644
--- a/generic/models.py
+++ b/generic/models.py
@@ -1993,8 +1993,13 @@ class ExamCollection(models.Model, AuthorMixin):
 
             for exam in exams:
                 # Each exam model exposes a `user_user_groups` ManyToManyField
-                exam.user_user_groups.add(*groups_qs)
-                updated += 1
+                try:
+                    exam.user_user_groups.add(*groups_qs)
+                    # Ensure any downstream signals / caches see the change
+                    exam.save()
+                    updated += 1
+                except Exception as e:
+                    logger.exception("Failed to add user_user_groups to exam %s: %s", getattr(exam, 'pk', exam), e)
 
         return updated
 
@@ -2027,8 +2032,12 @@ class ExamCollection(models.Model, AuthorMixin):
 
             for exam in exams:
                 # Each exam model exposes a `cid_user_groups` ManyToManyField
-                exam.cid_user_groups.add(*groups_qs)
-                updated += 1
+                try:
+                    exam.cid_user_groups.add(*groups_qs)
+                    exam.save()
+                    updated += 1
+                except Exception as e:
+                    logger.exception("Failed to add cid_user_groups to exam %s: %s", getattr(exam, 'pk', exam), e)
 
         return updated
 
diff --git a/generic/templates/generic/partials/user_search_widget_results.html b/generic/templates/generic/partials/user_search_widget_results.html
new file mode 100644
index 00000000..5ea7b4d3
--- /dev/null
+++ b/generic/templates/generic/partials/user_search_widget_results.html
@@ -0,0 +1,14 @@
+{% if results %}
+  <ul class="list-unstyled mb-0">
+    {% for item in results %}
+      <li class="py-1 d-flex justify-content-between align-items-center">
+        <div class="flex-grow-1">{{ item.text|escape }}</div>
+        <div>
+          <button type="button" class="btn btn-sm btn-primary" onclick="addUserToField('{{ field }}', {{ item.id }}, '{{ item.text|escapejs }}')">Add</button>
+        </div>
+      </li>
+    {% endfor %}
+  </ul>
+{% else %}
+  <div><em>No users found</em></div>
+{% endif %}
diff --git a/generic/urls.py b/generic/urls.py
index 6facc40f..7e7464bb 100755
--- a/generic/urls.py
+++ b/generic/urls.py
@@ -58,6 +58,7 @@ urlpatterns = [
         name="supervisor-autocomplete",
     ),
     path("user-search/", views.user_search, name="user_search"),
+    path("user-search-widget/", views.user_search_widget, name="user_search_widget"),
     path("supervisor-search/", views.supervisor_search, name="supervisor_search"),
     path(
         "cids/manage/<int:pk>/update", views.CidUserUpdate.as_view(), name="update_cid"
diff --git a/generic/views.py b/generic/views.py
index 81e96b8e..16b9745e 100644
--- a/generic/views.py
+++ b/generic/views.py
@@ -5908,6 +5908,35 @@ def user_search(request):
     return render(request, "generic/partials/user_search_results.html", {"results": results, "row": row, "q": q})
 
 
+@login_required
+def user_search_widget(request):
+    """HTMX/JS endpoint to search users for generic selectors.
+
+    Accepts GET params:
+      - q: query string
+      - field: the form field name to return with the results (so the
+               template can call addUserToField(field, id, text)).
+
+    Returns a small HTML fragment listing up to 10 matching users. Each
+    result will call `addUserToField(field, id, text)` when clicked.
+    """
+    q = (request.GET.get("q") or "").strip()
+    field = request.GET.get("field") or request.GET.get("row")
+    if not q:
+        return HttpResponse("")
+
+    users_qs = User.objects.filter(
+        Q(first_name__icontains=q)
+        | Q(last_name__icontains=q)
+        | Q(email__icontains=q)
+        | Q(username__icontains=q)
+    ).order_by("last_name", "first_name")[:10]
+
+    results = [{"id": u.pk, "text": f"{u.get_full_name() or u.username} - {u.email or ''}"} for u in users_qs]
+
+    return render(request, "generic/partials/user_search_widget_results.html", {"results": results, "field": field, "q": q})
+
+
 @login_required
 def supervisor_search(request):
     """HTMX endpoint to search supervisors for the trainees bulk-update UI.