diff --git a/conf/example.json b/conf/example.json
index 4db7b20..63ec3b1 100644
--- a/conf/example.json
+++ b/conf/example.json
@@ -1,5 +1,4 @@
 {
 	"view_mode": "table",
-	"calendar_id": 6,
 	"timezone_shift": 0
 }
diff --git a/data/example.kal.json b/data/example.kal.json
index 47cc274..e0b12aa 100644
--- a/data/example.kal.json
+++ b/data/example.kal.json
@@ -63,7 +63,7 @@
 	],
 	"calendars": [
 		{
-			"id": 5,
+			"id": 1,
 			"object": {
 				"kind": "concrete",
 				"data": {
@@ -123,7 +123,7 @@
 			}
 		},
 		{
-			"id": 3,
+			"id": 2,
 			"object": {
 				"kind": "concrete",
 				"data": {
@@ -198,7 +198,7 @@
 			}
 		},
 		{
-			"id": 4,
+			"id": 3,
 			"object": {
 				"kind": "concrete",
 				"data": {
@@ -226,7 +226,7 @@
 			}
 		},
 		{
-			"id": 1,
+			"id": 4,
 			"object": {
 				"kind": "concrete",
 				"data": {
@@ -283,7 +283,7 @@
 			}
 		},
 		{
-			"id": 2,
+			"id": 5,
 			"object": {
 				"kind": "concrete",
 				"data": {
@@ -333,27 +333,11 @@
 		},
 		{
 			"id": 6,
-			"object": {
-				"kind": "collection",
-				"data": {
-					"name": "Überblick",
-					"sources": [
-						1,
-						2,
-						3,
-						4,
-						5
-					]
-				}
-			}
-		},
-		{
-			"id": 7,
 			"object": {
 				"kind": "caldav",
 				"data": {
 					"name": "Lixer",
-					"private": false,
+					"private": true,
 					"read_only": true,
 					"source_url": "https://export.kalender.digital/ics/0/3e10dae66950379d4cc8/gesamterkalender.ics?past_months=3&future_months=36"
 				}
diff --git a/doc/konzept.md b/doc/konzept.md
index e8bb6fa..34ba108 100644
--- a/doc/konzept.md
+++ b/doc/konzept.md
@@ -1,5 +1,6 @@
 - Kalender sollen unabhängig von Nutzern bestehen können
 - einem Kalender können beliebig viele Nutzer zugeordnet werden, die jeweils bestimmte Berechtigungen haben (z.B. als Rollen "admin", "editor", "viewer", …)
+- Events bilden keine Domäne
 - Berechtigungen:
 	- Kalender anlegen
 	- Kalender-Stammdaten ändern
@@ -11,11 +12,10 @@
 - es gibt verschiedene Arten von Kalendern:
 	- konkret
 		- enthält Veranstaltungen
-	- Sammlung
-		- enthält selbst keine Veranstaltungen
-		- verweist auf beliebig viele andere Kalender (Kreise vermeiden)
 	- extern
 		- über CalDAV
 		- sollte read-only- und read/write-Modus haben
-- nach dem Anmelden sieht man eine Liste mit öffentlichen Kalendern, gruppiert nach jewiliger Rolle
+- nach dem Anmelden sieht man eine Kalender-Ansicht mit folgenden Kalendern kombiniert angezeigt:
+	- öffentliche Kalender
+	- nicht öffentliche Kalendar, bei welchen man Lese-Berechtigung hat
 - Entwurfsname: "zeitbild"
diff --git a/source/logic/backend.ts b/source/logic/backend.ts
index 7a71b2c..ccb2f05 100644
--- a/source/logic/backend.ts
+++ b/source/logic/backend.ts
@@ -130,14 +130,6 @@ namespace _zeitbild.frontend.resources.backend
 							};
 							break;
 						}
-						case "collection": {
-							return {
-								"key": calendar_entry.id,
-								"preview": {
-									"name": calendar_entry.object.data.name,
-								}
-							};
-						}
 						case "caldav": {
 							return {
 								"key": calendar_entry.id,
@@ -179,7 +171,7 @@ namespace _zeitbild.frontend.resources.backend
 	 * @todo prevent loops
 	 */
 	export async function calendar_gather_events(
-		calendar_id : type_calendar_id,
+		calendar_ids : Array<type_calendar_id>,
 		from_pit : _zeitbild.frontend.helpers.type_pit,
 		to_pit : _zeitbild.frontend.helpers.type_pit
 	) : Promise<
@@ -192,148 +184,150 @@ namespace _zeitbild.frontend.resources.backend
 		>
 	>
 	{
-		await init();
-		const calendar_object : type_calendar_object = await calendar_read(
-			calendar_id
-		);
 		lib_plankton.log.info(
 			"calendar_gather_events",
 			{
-				"calendar_id": calendar_id,
+				"calendar_ids": calendar_ids,
 			}
 		);
-		switch (calendar_object.kind) {
-			case "concrete": {
-				return Promise.resolve(
-					calendar_object.data.events
-					.filter(
-						(event) => _zeitbild.frontend.helpers.pit_is_between(
-							_zeitbild.frontend.helpers.pit_from_datetime(event.begin),
-							from_pit,
-							to_pit
-						)
-					)
-					.map(
-						(event) => ({
-							"calendar_id": calendar_id,
-							"calendar_name": calendar_object.data.name,
-							"event": event
-						})
-					)
-				);
-				break;
+		await init();
+		let result : Array<
+			{
+				calendar_id : type_calendar_id;
+				calendar_name : string;
+				event : type_event;
 			}
-			case "collection": {
-				return (
-					Promise.all(
-						calendar_object.data.sources
-						.map(
-							(source_calendar_id) => calendar_gather_events(
-								source_calendar_id,
-								from_pit,
-								to_pit
-							)
-						)
-					)
-					.then(
-						(entries) => Promise.resolve(
-							entries
-							.reduce(
-								(x, y) => x.concat(y),
-								[]
-							)
-						)
-					)
-				);
-				break;
-			}
-			case "caldav": {
-				const url : lib_plankton.url.type_url = lib_plankton.url.decode(
-					calendar_object.data.source_url
-				);
-				const http_request : lib_plankton.http.type_request = {
-					"version": "HTTP/2",
-					"scheme": ((url.scheme === "https") ? "https" : "http"),
-					"host": url.host,
-					"path": (url.path ?? "/"),
-					"query": url.query,
-					"method": lib_plankton.http.enum_method.get,
-					"headers": {},
-					"body": null,
-				};
-				// TODO: cache?
-				const http_response : lib_plankton.http.type_response = await lib_plankton.http.call(
-					http_request,
+		> = [];
+		for await (const calendar_id of calendar_ids) {
+			const calendar_object : type_calendar_object = await calendar_read(
+				calendar_id
+			);
+			if (calendar_object.data.private) {
+				lib_plankton.log.info(
+					"calendar_gather_events_private_calendar_blocked",
 					{
+						"calendar_id": calendar_id,
 					}
 				);
-				const vcalendar : lib_plankton.ical.type_vcalendar = lib_plankton.ical.ics_decode(
-					http_response.body.toString(),
-					{
+			}
+			else {
+				switch (calendar_object.kind) {
+					case "concrete": {
+						result = (
+							result
+							.concat(
+								calendar_object.data.events
+								.filter(
+									(event) => _zeitbild.frontend.helpers.pit_is_between(
+										_zeitbild.frontend.helpers.pit_from_datetime(event.begin),
+										from_pit,
+										to_pit
+									)
+								)
+								.map(
+									(event) => ({
+										"calendar_id": calendar_id,
+										"calendar_name": calendar_object.data.name,
+										"event": event
+									})
+								)
+							)
+						);
+						break;
 					}
-				);
-				return Promise.resolve(
-					vcalendar.vevents
-					.map(
-						(vevent : lib_plankton.ical.type_vevent) => (
-							(vevent.dtstart !== undefined)
-							?
+					case "caldav": {
+						const url : lib_plankton.url.type_url = lib_plankton.url.decode(
+							calendar_object.data.source_url
+						);
+						const http_request : lib_plankton.http.type_request = {
+							"version": "HTTP/2",
+							"scheme": ((url.scheme === "https") ? "https" : "http"),
+							"host": url.host,
+							"path": (url.path ?? "/"),
+							"query": url.query,
+							"method": lib_plankton.http.enum_method.get,
+							"headers": {},
+							"body": null,
+						};
+						// TODO: cache?
+						const http_response : lib_plankton.http.type_response = await lib_plankton.http.call(
+							http_request,
 							{
-								"name": (
-									(vevent.summary !== undefined)
-									?
-									vevent.summary
-									:
-									"???"
-								),
-								"begin": _zeitbild.frontend.helpers.ical_dt_to_own_datetime(vevent.dtstart),
-								"end": (
-									(vevent.dtend !== undefined)
-									?
-									_zeitbild.frontend.helpers.ical_dt_to_own_datetime(vevent.dtend)
-									:
-									null
-								),
-								"location": (
-									(vevent.location !== undefined)
-									?
-									vevent.location
-									:
-									null
-								),
-								"description": (
-									(vevent.description !== undefined)
-									?
-									vevent.description
-									:
-									null
-								),
 							}
-							:
-							null
-						)
-					)
-					.filter(
-						(event) => (event !== null)
-					)
-					.filter(
-						(event) => _zeitbild.frontend.helpers.pit_is_between(
-							_zeitbild.frontend.helpers.pit_from_datetime(event.begin),
-							from_pit,
-							to_pit
-						)
-					)
-					.map(
-						(event) => ({
-							"calendar_id": calendar_id,
-							"calendar_name": calendar_object.data.name,
-							"event": event,
-						})
-					)
-				);
-				break;
+						);
+						const vcalendar : lib_plankton.ical.type_vcalendar = lib_plankton.ical.ics_decode(
+							http_response.body.toString(),
+							{
+							}
+						);
+						result = (
+							result
+							.concat(
+								vcalendar.vevents
+								.map(
+									(vevent : lib_plankton.ical.type_vevent) => (
+										(vevent.dtstart !== undefined)
+										?
+										{
+											"name": (
+												(vevent.summary !== undefined)
+												?
+												vevent.summary
+												:
+												"???"
+											),
+											"begin": _zeitbild.frontend.helpers.ical_dt_to_own_datetime(vevent.dtstart),
+											"end": (
+												(vevent.dtend !== undefined)
+												?
+												_zeitbild.frontend.helpers.ical_dt_to_own_datetime(vevent.dtend)
+												:
+												null
+											),
+											"location": (
+												(vevent.location !== undefined)
+												?
+												vevent.location
+												:
+												null
+											),
+											"description": (
+												(vevent.description !== undefined)
+												?
+												vevent.description
+												:
+												null
+											),
+										}
+										:
+										null
+									)
+								)
+								.filter(
+									(event) => (event !== null)
+								)
+								.filter(
+									(event) => _zeitbild.frontend.helpers.pit_is_between(
+										_zeitbild.frontend.helpers.pit_from_datetime(event.begin),
+										from_pit,
+										to_pit
+									)
+								)
+								.map(
+									(event) => ({
+										"calendar_id": calendar_id,
+										"calendar_name": calendar_object.data.name,
+										"event": event,
+									})
+								)
+							)
+						);
+						break;
+					}
+				}
 			}
 		}
+		return Promise.resolve(result);
 	}
 
 }
diff --git a/source/logic/main.ts b/source/logic/main.ts
index 35b3327..4a123f4 100644
--- a/source/logic/main.ts
+++ b/source/logic/main.ts
@@ -7,11 +7,87 @@ namespace _zeitbild.frontend
 	 */
 	type type_conf = {
 		view_mode : string;
-		calendar_id : int;
+		calendar_ids : Array<int>;
 		timezone_shift : int;
 	};
 	
 	
+	/**
+	 */
+	async function render(
+		conf : type_conf,
+		calendar_ids : Array<type_calendar_id>
+	) : Promise<void>
+	{
+		calendar_ids.sort();
+		const target : HTMLElement = (document.querySelector("body") as HTMLBodyElement);
+		switch (conf.view_mode) {
+			default: {
+				throw (new Error("invalid view mode"));
+				break;
+			}
+			case "table": {
+				const content : string = await _zeitbild.frontend.view.calendar_view_table_html(
+					calendar_ids,
+					{
+						"from": {
+							"year": 2024,
+							"week": 35
+						},
+						"to": {
+							"year": 2024,
+							"week": 43
+						},
+						"timezone_shift": conf.timezone_shift,
+					}
+				);
+				target.innerHTML = content;
+				/*
+				document.querySelectorAll(".tableview-sources-entry").forEach(
+					(element) => {
+						element.addEventListener(
+							"click",
+							(event) => {
+								const element_ : HTMLElement = (event.target as HTMLElement);
+								const calendar_id : type_calendar_id = parseInt(element_.getAttribute("rel") as string);
+								const active : boolean = element_.classList.toggle("tableview-sources-entry-active");
+								render(
+									conf,
+									lib_plankton.call.convey(
+										calendar_ids,
+										[
+											(x : Array<int>) => (
+												active
+												?
+												calendar_ids.concat([calendar_id])
+												:
+												calendar_ids.filter(y => (y !== calendar_id))
+											),
+										]
+									)
+								);
+							}
+						);
+					}
+				);
+				 */
+				break;
+			}
+			case "list": {
+				const content : string = await _zeitbild.frontend.view.calendar_view_list_html(
+					calendar_ids,
+					{
+						"timezone_shift": conf.timezone_shift,
+					}
+				);
+				target.innerHTML = content;
+				break;
+			}
+		}
+		return Promise.resolve<void>(undefined);
+	}
+	
+	
 	/**
 	 */
 	export async function main(
@@ -27,42 +103,29 @@ namespace _zeitbild.frontend
 		// conf
 		const conf : type_conf = lib_plankton.json.decode(await lib_plankton.file.read("conf.json"));
 		
+		// args
+		
+		const url : URL = new URL(window.location.toString());
+		const calendar_ids : Array<type_calendar_id> = (
+			(url.searchParams.get("ids") !== null)
+			?
+			lib_plankton.call.convey(
+				url.searchParams.get("ids"),
+				[
+					(x : string) => lib_plankton.string.split(x, ","),
+					(x : Array<string>) => x.map(y => parseInt(y)),
+				]
+			)
+			:
+			(await _zeitbild.frontend.resources.backend.calendar_list()).map(x => x.key)
+		);
+		
 		// exec
-		let content : string;
-		switch (conf.view_mode) {
-			default: {
-				content = "";
-				throw (new Error("invalid view mode"));
-				break;
-			}
-			case "table": {
-				content = await _zeitbild.frontend.view.calendar_view_table_html(
-					conf.calendar_id,
-					{
-						"from": {
-							"year": 2024,
-							"week": 35
-						},
-						"to": {
-							"year": 2024,
-							"week": 43
-						},
-						"timezone_shift": conf.timezone_shift,
-					}
-				);
-				break;
-			}
-			case "list": {
-				content = await _zeitbild.frontend.view.calendar_view_list_html(
-					conf.calendar_id,
-					{
-						"timezone_shift": conf.timezone_shift,
-					}
-				);
-				break;
-			}
-		}
-		(document.querySelector("body") as HTMLBodyElement).innerHTML = content;
+		await render(
+			conf,
+			calendar_ids
+		);
+		
 		return Promise.resolve<void>(undefined);
 	}
 	
diff --git a/source/logic/types.ts b/source/logic/types.ts
index ac17b04..1cff1b8 100644
--- a/source/logic/types.ts
+++ b/source/logic/types.ts
@@ -3,7 +3,7 @@
  */
 namespace _zeitbild.frontend
 {
-
+	
 	/**
 	 */
 	type type_role = (
@@ -11,8 +11,8 @@ namespace _zeitbild.frontend
 		|
 		"viewer"
 	);
-
-
+	
+	
 	/**
 	 */
 	type type_user_id = int;
@@ -46,13 +46,13 @@ namespace _zeitbild.frontend
 			string
 		);
 	};
-
-
+	
+	
 	/**
 	 */
 	export type type_calendar_id = int;
-
-
+	
+	
 	/**
 	 * @todo bei "collection" Kreise vermeiden
 	 */
@@ -72,17 +72,6 @@ namespace _zeitbild.frontend
 			};
 		}
 		|
-		{
-			kind : "collection";
-			data : {
-				name : string;
-				private : boolean;
-				sources : Array<
-					type_calendar_id
-				>;
-			}
-		}
-		|
 		{
 			kind : "caldav";
 			data : {
@@ -93,8 +82,8 @@ namespace _zeitbild.frontend
 			}
 		}
 	);
-
-
+	
+	
 	/**
 	 */
 	export type type_datamodel = {
diff --git a/source/logic/view.ts b/source/logic/view.ts
index b44f838..48db65c 100644
--- a/source/logic/view.ts
+++ b/source/logic/view.ts
@@ -65,7 +65,7 @@ namespace _zeitbild.frontend.view
 										{
 											"year": event.end.date.year.toFixed(0).padStart(4, "0"),
 											"month": event.end.date.month.toFixed(0).padStart(2, "0"),
-											"day": event.end.date.month.toFixed(0).padStart(2, "0"),
+											"day": event.end.date.day.toFixed(0).padStart(2, "0"),
 										}
 									)
 									:
@@ -134,7 +134,7 @@ namespace _zeitbild.frontend.view
 	 * @todo kein "while"
 	 */
 	async function calendar_view_table_data(
-		calendar_id : type_calendar_id,
+		calendar_ids : Array<type_calendar_id>,
 		options : {
 			from ?: {
 				year : int;
@@ -232,7 +232,7 @@ namespace _zeitbild.frontend.view
 				event : type_event;
 			}
 		> = await _zeitbild.frontend.resources.backend.calendar_gather_events(
-			calendar_id,
+			calendar_ids,
 			from_pit,
 			to_pit
 		);
@@ -389,7 +389,7 @@ namespace _zeitbild.frontend.view
 	/**
 	 */
 	export async function calendar_view_table_html(
-		calendar_id : type_calendar_id,
+		calendar_ids : Array<type_calendar_id>,
 		options : {
 			from ?: {
 				year : int;
@@ -428,7 +428,7 @@ namespace _zeitbild.frontend.view
 				}
 			>;
 		} = await calendar_view_table_data(
-			calendar_id,
+			calendar_ids,
 			options
 		);
 		const sources : lib_plankton.structures.type_hashmap<
@@ -448,7 +448,7 @@ namespace _zeitbild.frontend.view
 					"value": {
 						"name": pair.value.name,
 						"color": lib_plankton.color.give_generic(
-							(pair.key + 0.2),
+							(pair.key - 1),
 							{
 								"saturation": 0.375,
 								"value": 0.375,
@@ -470,6 +470,7 @@ namespace _zeitbild.frontend.view
 								{
 									"name": data.name,
 									"color": lib_plankton.color.output_hex(data.color),
+									"rel": calendar_id.toFixed(0),
 								}
 							)
 						)
@@ -567,7 +568,7 @@ namespace _zeitbild.frontend.view
 	/**
 	 */
 	async function calendar_view_list_data(
-		calendar_id : type_calendar_id,
+		calendar_ids : Array<type_calendar_id>,
 		options : {
 			from ?: _zeitbild.frontend.helpers.type_pit;
 			to ?: _zeitbild.frontend.helpers.type_pit;
@@ -608,7 +609,7 @@ namespace _zeitbild.frontend.view
 				event : type_event;
 			}
 		> = await _zeitbild.frontend.resources.backend.calendar_gather_events(
-			calendar_id,
+			calendar_ids,
 			(options.from as _zeitbild.frontend.helpers.type_pit),
 			(options.to as _zeitbild.frontend.helpers.type_pit)
 		);
@@ -628,7 +629,7 @@ namespace _zeitbild.frontend.view
 	/**
 	 */
 	export async function calendar_view_list_html(
-		calendar_id : type_calendar_id,
+		calendar_ids : Array<type_calendar_id>,
 		options : {
 			from ?: _zeitbild.frontend.helpers.type_pit;
 			to ?: _zeitbild.frontend.helpers.type_pit;
@@ -642,7 +643,7 @@ namespace _zeitbild.frontend.view
 				event : type_event;
 			}
 		> = await calendar_view_list_data(
-			calendar_id,
+			calendar_ids,
 			options
 		);
 		return Promise.resolve<string>(
diff --git a/source/style/main.css b/source/style/main.css
index aeabb9b..61cd645 100644
--- a/source/style/main.css
+++ b/source/style/main.css
@@ -22,11 +22,17 @@ html {
 	margin: 0;
 	padding: 0;
 	list-style-type: none;
+	font-size: 0.75em;
 }
 
 .tableview-sources-entry {
 	margin: 8px;
 	padding: 4px;
+	cursor: pointer;
+}
+
+.tableview-sources-entry:not(.tableview-sources-entry-active) {
+	filter: saturate(0);
 }
 
 .calendar table {
diff --git a/source/templates/tableview-sources-entry.html.tpl b/source/templates/tableview-sources-entry.html.tpl
index a78d64c..861ea42 100644
--- a/source/templates/tableview-sources-entry.html.tpl
+++ b/source/templates/tableview-sources-entry.html.tpl
@@ -1 +1 @@
-			<li class="tableview-sources-entry" style="background-color: {{color}}">{{name}}</li>
+			<li class="tableview-sources-entry tableview-sources-entry-active" style="background-color: {{color}}" rel="{{rel}}">{{name}}</li>