diff --git a/src/rules/WindowRuleEnforcer.ts b/src/rules/WindowRuleEnforcer.ts
index f228af7..561d2eb 100644
--- a/src/rules/WindowRuleEnforcer.ts
+++ b/src/rules/WindowRuleEnforcer.ts
@@ -31,8 +31,9 @@ class WindowRuleEnforcer {
         manager.connect(kwinClient.captionChanged, () => {
             const shouldTile = enforcer.shouldTile(kwinClient);
             world.do((clientManager, desktopManager) => {
-                if (shouldTile) {
-                    clientManager.tileClient(kwinClient);
+                const desktop = desktopManager.getDesktopForClient(kwinClient);
+                if (shouldTile && desktop !== undefined) {
+                    clientManager.tileClient(kwinClient, desktop.grid);
                 } else {
                     clientManager.untileClient(kwinClient);
                 }
diff --git a/src/world/ClientManager.ts b/src/world/ClientManager.ts
index 4a3a707..fa349e9 100644
--- a/src/world/ClientManager.ts
+++ b/src/world/ClientManager.ts
@@ -27,13 +27,13 @@ class ClientManager {
 
     public addClient(kwinClient: KwinClient) {
         console.assert(!this.hasClient(kwinClient));
+        const desktop = this.desktopManager.getDesktopForClient(kwinClient);
 
         let constructState: (client: ClientWrapper) => ClientState.State;
         if (kwinClient.dock) {
             constructState = () => new ClientState.Docked(this.world, kwinClient);
-        } else if (this.windowRuleEnforcer.shouldTile(kwinClient)) {
-            const grid = this.desktopManager.getDesktopForClient(kwinClient).grid;
-            constructState = (client: ClientWrapper) => new ClientState.Tiled(this.world, client, grid);
+        } else if (this.windowRuleEnforcer.shouldTile(kwinClient) && desktop !== undefined) {
+            constructState = (client: ClientWrapper) => new ClientState.Tiled(this.world, client, desktop.grid);
         } else {
             constructState = (client: ClientWrapper) => new ClientState.Floating(this.world, client, this.config, false);
         }
@@ -86,12 +86,16 @@ class ClientManager {
             return;
         }
         if (client.stateManager.getState() instanceof ClientState.TiledMinimized) {
-            const grid = this.desktopManager.getDesktopForClient(kwinClient).grid;
-            client.stateManager.setState(() => new ClientState.Tiled(this.world, client, grid), false);
+            const desktop = this.desktopManager.getDesktopForClient(kwinClient);
+            if (desktop !== undefined) {
+                client.stateManager.setState(() => new ClientState.Tiled(this.world, client, desktop.grid), false);
+            } else {
+                client.stateManager.setState(() => new ClientState.Floating(this.world, client, this.config, false), false);
+            }
         }
     }
 
-    public tileClient(kwinClient: KwinClient) {
+    public tileClient(kwinClient: KwinClient, grid: Grid) {
         const client = this.clientMap.get(kwinClient);
         if (client === undefined) {
             return;
@@ -99,7 +103,6 @@ class ClientManager {
         if (client.stateManager.getState() instanceof ClientState.Tiled) {
             return;
         }
-        const grid = this.desktopManager.getDesktopForClient(kwinClient).grid;
         client.stateManager.setState(() => new ClientState.Tiled(this.world, client, grid), false);
     }
 
@@ -147,8 +150,11 @@ class ClientManager {
         const clientState = client.stateManager.getState();
         if ((clientState instanceof ClientState.Floating || clientState instanceof ClientState.Pinned) && Clients.canTileEver(kwinClient)) {
             Clients.makeTileable(kwinClient);
-            const grid = this.desktopManager.getDesktopForClient(kwinClient).grid;
-            client.stateManager.setState(() => new ClientState.Tiled(this.world, client, grid), false);
+            const desktop = this.desktopManager.getDesktopForClient(kwinClient);
+            if (desktop === undefined) {
+                return;
+            }
+            client.stateManager.setState(() => new ClientState.Tiled(this.world, client, desktop.grid), false);
         } else if (clientState instanceof ClientState.Tiled) {
             client.stateManager.setState(() => new ClientState.Floating(this.world, client, this.config, true), false);
         }
diff --git a/src/world/DesktopManager.ts b/src/world/DesktopManager.ts
index f57d103..dd4f3c2 100644
--- a/src/world/DesktopManager.ts
+++ b/src/world/DesktopManager.ts
@@ -39,7 +39,9 @@ class DesktopManager {
     }
 
     public getDesktopForClient(kwinClient: KwinClient) {
-        console.assert(kwinClient.activities.length === 1 && kwinClient.desktop > 0);
+        if (kwinClient.activities.length !== 1 && kwinClient.desktop === 0) {
+            return undefined;
+        }
         return this.getDesktop(kwinClient.activities[0], kwinClient.desktop);
     }
 
diff --git a/src/world/clientState/Tiled.ts b/src/world/clientState/Tiled.ts
index ffd0b31..5a04067 100644
--- a/src/world/clientState/Tiled.ts
+++ b/src/world/clientState/Tiled.ts
@@ -33,23 +33,25 @@ namespace ClientState {
 
             manager.connect(kwinClient.desktopChanged, () => {
                 world.do((clientManager, desktopManager) => {
-                    if (kwinClient.desktop === -1) {
+                    const desktop = desktopManager.getDesktopForClient(kwinClient);
+                    if (desktop === undefined) {
                         // windows on all desktops are not supported
                         clientManager.untileClient(kwinClient);
                         return;
                     }
-                    Tiled.moveWindowToCorrectGrid(desktopManager, window);
+                    Tiled.moveWindowToGrid(window, desktop.grid);
                 });
             });
 
             manager.connect(kwinClient.activitiesChanged, () => {
                 world.do((clientManager, desktopManager) => {
-                    if (kwinClient.activities.length !== 1) {
+                    const desktop = desktopManager.getDesktopForClient(kwinClient);
+                    if (desktop === undefined) {
                         // windows on multiple activities are not supported
                         clientManager.untileClient(kwinClient);
                         return;
                     }
-                    Tiled.moveWindowToCorrectGrid(desktopManager, window);
+                    Tiled.moveWindowToGrid(window, desktop.grid);
                 });
             })
 
@@ -130,17 +132,13 @@ namespace ClientState {
             return manager;
         }
 
-        private static moveWindowToCorrectGrid(desktopManager: DesktopManager, window: Window) {
-            const kwinClient = window.client.kwinClient;
-
-            const oldGrid = window.column.grid;
-            const newGrid = desktopManager.getDesktopForClient(kwinClient).grid;
-            if (oldGrid === newGrid) {
-                // window already on the correct grid
+        private static moveWindowToGrid(window: Window, grid: Grid) {
+            if (grid === window.column.grid) {
+                // window already on the given grid
                 return;
             }
 
-            const newColumn = new Column(newGrid, newGrid.getLastFocusedColumn() ?? newGrid.getLastColumn());
+            const newColumn = new Column(grid, grid.getLastFocusedColumn() ?? grid.getLastColumn());
             window.moveToColumn(newColumn);
         }