diff --git a/ui/src/components/IssuesList.tsx b/ui/src/components/IssuesList.tsx
index 952c649a..6d56704d 100644
--- a/ui/src/components/IssuesList.tsx
+++ b/ui/src/components/IssuesList.tsx
@@ -219,6 +219,7 @@ export function IssuesList({
     return getViewState(scopedKey);
   });
   const [assigneePickerIssueId, setAssigneePickerIssueId] = useState<string | null>(null);
+  const [collapsedParents, setCollapsedParents] = useState<Set<string>>(new Set());
   const [assigneeSearch, setAssigneeSearch] = useState("");
   const [issueSearch, setIssueSearch] = useState(initialSearch ?? "");
   const deferredIssueSearch = useDeferredValue(issueSearch);
@@ -320,251 +321,6 @@ export function IssuesList({
     setAssigneeSearch("");
   }, [onUpdateIssue]);
 
-  const listContent = useMemo(() => {
-    if (viewState.viewMode === "board") {
-      return (
-        <KanbanBoard
-          issues={filtered}
-          agents={agents}
-          liveIssueIds={liveIssueIds}
-          onUpdateIssue={onUpdateIssue}
-        />
-      );
-    }
-
-    return groupedContent.map((group) => (
-      <Collapsible
-        key={group.key}
-        open={!viewState.collapsedGroups.includes(group.key)}
-        onOpenChange={(open) => {
-          updateView({
-            collapsedGroups: open
-              ? viewState.collapsedGroups.filter((k) => k !== group.key)
-              : [...viewState.collapsedGroups, group.key],
-          });
-        }}
-      >
-        {group.label && (
-          <div className="flex items-center py-1.5 pl-1 pr-3">
-            <CollapsibleTrigger className="flex items-center gap-1.5">
-              <ChevronRight className="h-3.5 w-3.5 shrink-0 text-muted-foreground transition-transform [[data-state=open]>&]:rotate-90" />
-              <span className="text-sm font-semibold uppercase tracking-wide">
-                {group.label}
-              </span>
-            </CollapsibleTrigger>
-            <Button
-              variant="ghost"
-              size="icon-xs"
-              className="ml-auto text-muted-foreground"
-              onClick={() => openNewIssue(newIssueDefaults(group.key))}
-            >
-              <Plus className="h-3 w-3" />
-            </Button>
-          </div>
-        )}
-        <CollapsibleContent>
-          {group.items.map((issue) => (
-            <IssueRow
-              key={issue.id}
-              issue={issue}
-              issueLinkState={issueLinkState}
-              desktopLeadingSpacer
-              mobileLeading={(
-                <span
-                  onClick={(e) => {
-                    e.preventDefault();
-                    e.stopPropagation();
-                  }}
-                >
-                  <StatusIcon
-                    status={issue.status}
-                    onChange={(s) => onUpdateIssue(issue.id, { status: s })}
-                  />
-                </span>
-              )}
-              desktopMetaLeading={(
-                <>
-                  <span
-                    className="hidden shrink-0 sm:inline-flex"
-                    onClick={(e) => {
-                      e.preventDefault();
-                      e.stopPropagation();
-                    }}
-                  >
-                    <StatusIcon
-                      status={issue.status}
-                      onChange={(s) => onUpdateIssue(issue.id, { status: s })}
-                    />
-                  </span>
-                  <span className="shrink-0 font-mono text-xs text-muted-foreground">
-                    {issue.identifier ?? issue.id.slice(0, 8)}
-                  </span>
-                  {liveIssueIds?.has(issue.id) && (
-                    <span className="inline-flex items-center gap-1 rounded-full bg-blue-500/10 px-1.5 py-0.5 sm:gap-1.5 sm:px-2">
-                      <span className="relative flex h-2 w-2">
-                        <span className="absolute inline-flex h-full w-full animate-pulse rounded-full bg-blue-400 opacity-75" />
-                        <span className="relative inline-flex h-2 w-2 rounded-full bg-blue-500" />
-                      </span>
-                      <span className="hidden text-[11px] font-medium text-blue-600 dark:text-blue-400 sm:inline">
-                        Live
-                      </span>
-                    </span>
-                  )}
-                </>
-              )}
-              mobileMeta={timeAgo(issue.updatedAt)}
-              desktopTrailing={(
-                <>
-                  {(issue.labels ?? []).length > 0 && (
-                    <span className="hidden items-center gap-1 overflow-hidden md:flex md:max-w-[240px]">
-                      {(issue.labels ?? []).slice(0, 3).map((label) => (
-                        <span
-                          key={label.id}
-                          className="inline-flex items-center rounded-full border px-1.5 py-0.5 text-[10px] font-medium"
-                          style={{
-                            borderColor: label.color,
-                            color: pickTextColorForPillBg(label.color, 0.12),
-                            backgroundColor: `${label.color}1f`,
-                          }}
-                        >
-                          {label.name}
-                        </span>
-                      ))}
-                      {(issue.labels ?? []).length > 3 && (
-                        <span className="text-[10px] text-muted-foreground">
-                          +{(issue.labels ?? []).length - 3}
-                        </span>
-                      )}
-                    </span>
-                  )}
-                  <Popover
-                    open={assigneePickerIssueId === issue.id}
-                    onOpenChange={(open) => {
-                      setAssigneePickerIssueId(open ? issue.id : null);
-                      if (!open) setAssigneeSearch("");
-                    }}
-                  >
-                    <PopoverTrigger asChild>
-                      <button
-                        className="flex w-[180px] shrink-0 items-center rounded-md px-2 py-1 transition-colors hover:bg-accent/50"
-                        onClick={(e) => {
-                          e.preventDefault();
-                          e.stopPropagation();
-                        }}
-                      >
-                        {issue.assigneeAgentId && agentName(issue.assigneeAgentId) ? (
-                          <Identity name={agentName(issue.assigneeAgentId)!} size="sm" />
-                        ) : issue.assigneeUserId ? (
-                          <span className="inline-flex items-center gap-1.5 text-xs">
-                            <span className="inline-flex h-5 w-5 items-center justify-center rounded-full border border-dashed border-muted-foreground/35 bg-muted/30">
-                              <User className="h-3 w-3" />
-                            </span>
-                            {formatAssigneeUserLabel(issue.assigneeUserId, currentUserId) ?? "User"}
-                          </span>
-                        ) : (
-                          <span className="inline-flex items-center gap-1.5 text-xs text-muted-foreground">
-                            <span className="inline-flex h-5 w-5 items-center justify-center rounded-full border border-dashed border-muted-foreground/35 bg-muted/30">
-                              <User className="h-3 w-3" />
-                            </span>
-                            Assignee
-                          </span>
-                        )}
-                      </button>
-                    </PopoverTrigger>
-                    <PopoverContent
-                      className="w-56 p-1"
-                      align="end"
-                      onClick={(e) => e.stopPropagation()}
-                      onPointerDownOutside={() => setAssigneeSearch("")}
-                    >
-                      <input
-                        className="mb-1 w-full border-b border-border bg-transparent px-2 py-1.5 text-xs outline-none placeholder:text-muted-foreground/50"
-                        placeholder="Search assignees..."
-                        value={assigneeSearch}
-                        onChange={(e) => setAssigneeSearch(e.target.value)}
-                        autoFocus
-                      />
-                      <div className="max-h-48 overflow-y-auto overscroll-contain">
-                        <button
-                          className={cn(
-                            "flex w-full items-center gap-2 rounded px-2 py-1.5 text-xs hover:bg-accent/50",
-                            !issue.assigneeAgentId && !issue.assigneeUserId && "bg-accent",
-                          )}
-                          onClick={(e) => {
-                            e.preventDefault();
-                            e.stopPropagation();
-                            assignIssue(issue.id, null, null);
-                          }}
-                        >
-                          No assignee
-                        </button>
-                        {currentUserId && (
-                          <button
-                            className={cn(
-                              "flex w-full items-center gap-2 rounded px-2 py-1.5 text-left text-xs hover:bg-accent/50",
-                              issue.assigneeUserId === currentUserId && "bg-accent",
-                            )}
-                            onClick={(e) => {
-                              e.preventDefault();
-                              e.stopPropagation();
-                              assignIssue(issue.id, null, currentUserId);
-                            }}
-                          >
-                            <User className="h-3.5 w-3.5 shrink-0 text-muted-foreground" />
-                            <span>Me</span>
-                          </button>
-                        )}
-                        {(agents ?? [])
-                          .filter((agent) => {
-                            if (!assigneeSearch.trim()) return true;
-                            return agent.name
-                              .toLowerCase()
-                              .includes(assigneeSearch.toLowerCase());
-                          })
-                          .map((agent) => (
-                            <button
-                              key={agent.id}
-                              className={cn(
-                                "flex w-full items-center gap-2 rounded px-2 py-1.5 text-left text-xs hover:bg-accent/50",
-                                issue.assigneeAgentId === agent.id && "bg-accent",
-                              )}
-                              onClick={(e) => {
-                                e.preventDefault();
-                                e.stopPropagation();
-                                assignIssue(issue.id, agent.id, null);
-                              }}
-                            >
-                              <Identity name={agent.name} size="sm" className="min-w-0" />
-                            </button>
-                          ))}
-                      </div>
-                    </PopoverContent>
-                  </Popover>
-                </>
-              )}
-              trailingMeta={formatDate(issue.createdAt)}
-            />
-          ))}
-        </CollapsibleContent>
-      </Collapsible>
-    ));
-  }, [
-    agents,
-    agentName,
-    assigneePickerIssueId,
-    assigneeSearch,
-    assignIssue,
-    currentUserId,
-    filtered,
-    groupedContent,
-    issueLinkState,
-    liveIssueIds,
-    newIssueDefaults,
-    onUpdateIssue,
-    openNewIssue,
-    updateView,
-    viewState.collapsedGroups,
-  ]);
 
   return (
     <div className="space-y-4">
@@ -870,7 +626,261 @@ export function IssuesList({
         />
       )}
 
-      {listContent}
+      {viewState.viewMode === "board" ? (
+        <KanbanBoard
+          issues={filtered}
+          agents={agents}
+          liveIssueIds={liveIssueIds}
+          onUpdateIssue={onUpdateIssue}
+        />
+      ) : (
+        groupedContent.map((group) => (
+          <Collapsible
+            key={group.key}
+            open={!viewState.collapsedGroups.includes(group.key)}
+            onOpenChange={(open) => {
+              updateView({
+                collapsedGroups: open
+                  ? viewState.collapsedGroups.filter((k) => k !== group.key)
+                  : [...viewState.collapsedGroups, group.key],
+              });
+            }}
+          >
+            {group.label && (
+              <div className="flex items-center py-1.5 pl-1 pr-3">
+                <CollapsibleTrigger className="flex items-center gap-1.5">
+                  <ChevronRight className="h-3.5 w-3.5 shrink-0 text-muted-foreground transition-transform [[data-state=open]>&]:rotate-90" />
+                  <span className="text-sm font-semibold uppercase tracking-wide">
+                    {group.label}
+                  </span>
+                </CollapsibleTrigger>
+                <Button
+                  variant="ghost"
+                  size="icon-xs"
+                  className="ml-auto text-muted-foreground"
+                  onClick={() => openNewIssue(newIssueDefaults(group.key))}
+                >
+                  <Plus className="h-3 w-3" />
+                </Button>
+              </div>
+            )}
+            <CollapsibleContent>
+              {(() => {
+                const itemIds = new Set(group.items.map((i) => i.id));
+                const roots = group.items.filter((i) => !i.parentId || !itemIds.has(i.parentId));
+                const childMap = new Map<string, Issue[]>();
+                for (const item of group.items) {
+                  if (item.parentId && itemIds.has(item.parentId)) {
+                    const arr = childMap.get(item.parentId) ?? [];
+                    arr.push(item);
+                    childMap.set(item.parentId, arr);
+                  }
+                }
+
+                const renderIssueRow = (issue: Issue, isChild: boolean) => {
+                  const children = childMap.get(issue.id) ?? [];
+                  const hasChildren = children.length > 0;
+                  const isExpanded = !collapsedParents.has(issue.id);
+                  const toggleCollapse = (e: { preventDefault: () => void; stopPropagation: () => void }) => {
+                    e.preventDefault();
+                    e.stopPropagation();
+                    setCollapsedParents((prev) => {
+                      const next = new Set(prev);
+                      if (next.has(issue.id)) next.delete(issue.id); else next.add(issue.id);
+                      return next;
+                    });
+                  };
+
+                  return (
+                    <div key={issue.id}>
+                      <IssueRow
+                        issue={issue}
+                        issueLinkState={issueLinkState}
+                        className={isChild ? "pl-6" : undefined}
+                        mobileLeading={
+                          hasChildren ? (
+                            <button type="button" onClick={toggleCollapse}>
+                              <ChevronRight className={cn("h-3.5 w-3.5 transition-transform", isExpanded && "rotate-90")} />
+                            </button>
+                          ) : (
+                            <span onClick={(e) => { e.preventDefault(); e.stopPropagation(); }}>
+                              <StatusIcon status={issue.status} onChange={(s) => onUpdateIssue(issue.id, { status: s })} />
+                            </span>
+                          )
+                        }
+                        desktopMetaLeading={(
+                          <>
+                            {hasChildren ? (
+                              <button
+                                type="button"
+                                className="hidden shrink-0 items-center sm:inline-flex"
+                                onClick={toggleCollapse}
+                              >
+                                <ChevronRight className={cn("h-3.5 w-3.5 transition-transform", isExpanded && "rotate-90")} />
+                              </button>
+                            ) : (
+                              <span className="hidden w-3.5 shrink-0 sm:block" />
+                            )}
+                            <span
+                              className="hidden shrink-0 sm:inline-flex"
+                              onClick={(e) => { e.preventDefault(); e.stopPropagation(); }}
+                            >
+                              <StatusIcon status={issue.status} onChange={(s) => onUpdateIssue(issue.id, { status: s })} />
+                            </span>
+                            <span className="shrink-0 font-mono text-xs text-muted-foreground">
+                              {issue.identifier ?? issue.id.slice(0, 8)}
+                            </span>
+                            {liveIssueIds?.has(issue.id) && (
+                              <span className="inline-flex items-center gap-1 rounded-full bg-blue-500/10 px-1.5 py-0.5 sm:gap-1.5 sm:px-2">
+                                <span className="relative flex h-2 w-2">
+                                  <span className="absolute inline-flex h-full w-full animate-pulse rounded-full bg-blue-400 opacity-75" />
+                                  <span className="relative inline-flex h-2 w-2 rounded-full bg-blue-500" />
+                                </span>
+                                <span className="hidden text-[11px] font-medium text-blue-600 dark:text-blue-400 sm:inline">
+                                  Live
+                                </span>
+                              </span>
+                            )}
+                          </>
+                        )}
+                        mobileMeta={timeAgo(issue.updatedAt)}
+                        desktopTrailing={(
+                          <>
+                            {(issue.labels ?? []).length > 0 && (
+                              <span className="hidden items-center gap-1 overflow-hidden md:flex md:max-w-[240px]">
+                                {(issue.labels ?? []).slice(0, 3).map((label) => (
+                                  <span
+                                    key={label.id}
+                                    className="inline-flex items-center rounded-full border px-1.5 py-0.5 text-[10px] font-medium"
+                                    style={{
+                                      borderColor: label.color,
+                                      color: pickTextColorForPillBg(label.color, 0.12),
+                                      backgroundColor: `${label.color}1f`,
+                                    }}
+                                  >
+                                    {label.name}
+                                  </span>
+                                ))}
+                                {(issue.labels ?? []).length > 3 && (
+                                  <span className="text-[10px] text-muted-foreground">
+                                    +{(issue.labels ?? []).length - 3}
+                                  </span>
+                                )}
+                              </span>
+                            )}
+                            <Popover
+                              open={assigneePickerIssueId === issue.id}
+                              onOpenChange={(open) => {
+                                setAssigneePickerIssueId(open ? issue.id : null);
+                                if (!open) setAssigneeSearch("");
+                              }}
+                            >
+                              <PopoverTrigger asChild>
+                                <button
+                                  className="flex w-[180px] shrink-0 items-center rounded-md px-2 py-1 transition-colors hover:bg-accent/50"
+                                  onClick={(e) => { e.preventDefault(); e.stopPropagation(); }}
+                                >
+                                  {issue.assigneeAgentId && agentName(issue.assigneeAgentId) ? (
+                                    <Identity name={agentName(issue.assigneeAgentId)!} size="sm" />
+                                  ) : issue.assigneeUserId ? (
+                                    <span className="inline-flex items-center gap-1.5 text-xs">
+                                      <span className="inline-flex h-5 w-5 items-center justify-center rounded-full border border-dashed border-muted-foreground/35 bg-muted/30">
+                                        <User className="h-3 w-3" />
+                                      </span>
+                                      {formatAssigneeUserLabel(issue.assigneeUserId, currentUserId) ?? "User"}
+                                    </span>
+                                  ) : (
+                                    <span className="inline-flex items-center gap-1.5 text-xs text-muted-foreground">
+                                      <span className="inline-flex h-5 w-5 items-center justify-center rounded-full border border-dashed border-muted-foreground/35 bg-muted/30">
+                                        <User className="h-3 w-3" />
+                                      </span>
+                                      Assignee
+                                    </span>
+                                  )}
+                                </button>
+                              </PopoverTrigger>
+                              <PopoverContent
+                                className="w-56 p-1"
+                                align="end"
+                                onClick={(e) => e.stopPropagation()}
+                                onPointerDownOutside={() => setAssigneeSearch("")}
+                              >
+                                <input
+                                  className="mb-1 w-full border-b border-border bg-transparent px-2 py-1.5 text-xs outline-none placeholder:text-muted-foreground/50"
+                                  placeholder="Search assignees..."
+                                  value={assigneeSearch}
+                                  onChange={(e) => setAssigneeSearch(e.target.value)}
+                                  autoFocus
+                                />
+                                <div className="max-h-48 overflow-y-auto overscroll-contain">
+                                  <button
+                                    className={cn(
+                                      "flex w-full items-center gap-2 rounded px-2 py-1.5 text-xs hover:bg-accent/50",
+                                      !issue.assigneeAgentId && !issue.assigneeUserId && "bg-accent",
+                                    )}
+                                    onClick={(e) => {
+                                      e.preventDefault();
+                                      e.stopPropagation();
+                                      assignIssue(issue.id, null, null);
+                                    }}
+                                  >
+                                    No assignee
+                                  </button>
+                                  {currentUserId && (
+                                    <button
+                                      className={cn(
+                                        "flex w-full items-center gap-2 rounded px-2 py-1.5 text-left text-xs hover:bg-accent/50",
+                                        issue.assigneeUserId === currentUserId && "bg-accent",
+                                      )}
+                                      onClick={(e) => {
+                                        e.preventDefault();
+                                        e.stopPropagation();
+                                        assignIssue(issue.id, null, currentUserId);
+                                      }}
+                                    >
+                                      <User className="h-3.5 w-3.5 shrink-0 text-muted-foreground" />
+                                      <span>Me</span>
+                                    </button>
+                                  )}
+                                  {(agents ?? [])
+                                    .filter((agent) => {
+                                      if (!assigneeSearch.trim()) return true;
+                                      return agent.name.toLowerCase().includes(assigneeSearch.toLowerCase());
+                                    })
+                                    .map((agent) => (
+                                      <button
+                                        key={agent.id}
+                                        className={cn(
+                                          "flex w-full items-center gap-2 rounded px-2 py-1.5 text-left text-xs hover:bg-accent/50",
+                                          issue.assigneeAgentId === agent.id && "bg-accent",
+                                        )}
+                                        onClick={(e) => {
+                                          e.preventDefault();
+                                          e.stopPropagation();
+                                          assignIssue(issue.id, agent.id, null);
+                                        }}
+                                      >
+                                        <Identity name={agent.name} size="sm" className="min-w-0" />
+                                      </button>
+                                    ))}
+                                </div>
+                              </PopoverContent>
+                            </Popover>
+                          </>
+                        )}
+                        trailingMeta={formatDate(issue.createdAt)}
+                      />
+                      {hasChildren && isExpanded && children.map((child) => renderIssueRow(child, true))}
+                    </div>
+                  );
+                };
+
+                return roots.map((issue) => renderIssueRow(issue, false));
+              })()}
+            </CollapsibleContent>
+          </Collapsible>
+        ))
+      )}
     </div>
   );
 }