diff --git a/src/kanban/outboundMessages.ts b/src/kanban/outboundMessages.ts
index 9aef87c..64017cb 100644
--- a/src/kanban/outboundMessages.ts
+++ b/src/kanban/outboundMessages.ts
@@ -12,6 +12,7 @@ export type KanbanOutboundMessage =
 			scopeFilter: KanbanScopeFilter;
 			shownHiddenColumns: TaskStatus[];
 			defaultHiddenStatuses: TaskStatus[];
+			dangerStatuses: TaskStatus[];
 			availableScopes: TaskScope[];
 	  }
 	| { variant: "error"; error: AppError };
diff --git a/src/views/taskKanbanHtml.ts b/src/views/taskKanbanHtml.ts
index 92493d1..61a79b4 100644
--- a/src/views/taskKanbanHtml.ts
+++ b/src/views/taskKanbanHtml.ts
@@ -116,6 +116,13 @@ export function getTaskKanbanHtml(
       color: var(--vscode-button-foreground);
       border-color: transparent;
     }
+    #visibility-bar button.danger {
+      border-color: var(--vscode-errorForeground);
+      border-width: 2px;
+    }
+    #visibility-bar button.danger.shown {
+      background: var(--vscode-errorForeground);
+    }
     #status-line {
       font-size: 0.85em;
       opacity: 0.85;
@@ -210,6 +217,7 @@ export function getTaskKanbanHtml(
     let scopeFilter = "all";
     let shownHiddenColumns = [];
     let defaultHiddenStatuses = [];
+    let dangerStatuses = [];
     let availableScopes = [];
     let dragTaskId = null;
 
@@ -269,6 +277,9 @@ export function getTaskKanbanHtml(
         if (shownHiddenColumns.indexOf(status) >= 0) {
           btn.classList.add("shown");
         }
+        if (dangerStatuses.indexOf(status) >= 0) {
+          btn.classList.add("danger");
+        }
         btn.addEventListener("click", () => {
           post({ variant: "toggleHiddenColumn", status: status });
         });
@@ -374,6 +385,7 @@ export function getTaskKanbanHtml(
         scopeFilter = message.scopeFilter || "all";
         shownHiddenColumns = message.shownHiddenColumns || [];
         defaultHiddenStatuses = message.defaultHiddenStatuses || [];
+        dangerStatuses = message.dangerStatuses || [];
         availableScopes = message.availableScopes || [];
         setStatus("");
         render();
diff --git a/src/views/taskKanbanPanel.ts b/src/views/taskKanbanPanel.ts
index e6814c8..ccd3c57 100644
--- a/src/views/taskKanbanPanel.ts
+++ b/src/views/taskKanbanPanel.ts
@@ -278,10 +278,12 @@ export class TaskKanbanPanel {
 	}
 
 	#postState(): void {
-		const board = buildKanbanBoard(
-			this.#filteredTasks().map((item) => item.task),
-			{ shownHiddenColumns: this.#shownHiddenColumns },
-		);
+		const filtered = this.#filteredTasks().map((item) => item.task);
+		const board = buildKanbanBoard(filtered, {
+			shownHiddenColumns: this.#shownHiddenColumns,
+		});
+
+		const hasUnknown = filtered.some((t) => t.status === TaskStatus.UNKNOWN);
 
 		this.#post({
 			variant: "state",
@@ -289,9 +291,12 @@ export class TaskKanbanPanel {
 			scopeFilter: this.#scopeFilter,
 			shownHiddenColumns: this.#shownHiddenColumns,
 			defaultHiddenStatuses: TASK_STATUS_ORDER.filter(
-				(s) => TASK_STATUS_META[s].defaultHidden,
+				(s) =>
+					TASK_STATUS_META[s].defaultHidden &&
+					(s !== TaskStatus.UNKNOWN || hasUnknown),
 			),
 			availableScopes: this.#availableScopes(),
+			dangerStatuses: hasUnknown ? [TaskStatus.UNKNOWN] : [],
 		});
 	}
 
diff --git a/src/views/taskTreeProvider.ts b/src/views/taskTreeProvider.ts
index d2b4904..2cc5324 100644
--- a/src/views/taskTreeProvider.ts
+++ b/src/views/taskTreeProvider.ts
@@ -3,9 +3,9 @@ import { resolveTaskLocations } from "@/commands/resolveTaskLocations";
 import { Task } from "@/model/task";
 import { LocatedTask, TaskLocation } from "@/model/taskLocation";
 import {
+	TaskStatus,
 	TASK_STATUS_META,
 	TASK_STATUS_ORDER,
-	type TaskStatus,
 } from "@/model/taskStatus";
 import { IConfigProvider, ITaskRepository } from "@/ports";
 import { TASK_SCOPE_LABELS, TASK_STATUS_LABELS } from "@/ui/taskLabels";
@@ -47,7 +47,12 @@ class TaskGroupTreeItem extends vscode.TreeItem {
 		this.description = `(${tasks.length})`;
 		this.id = `group-${location.scope}-${status}`;
 		this.contextValue = "taskGroup";
-		this.iconPath = new vscode.ThemeIcon(TASK_STATUS_META[status].icon);
+		this.iconPath = new vscode.ThemeIcon(
+			TASK_STATUS_META[status].icon,
+			status === TaskStatus.UNKNOWN
+				? new vscode.ThemeColor("charts.red")
+				: undefined,
+		);
 	}
 }