diff --git a/CHANGELOG.unreleased.md b/CHANGELOG.unreleased.md
index 35a5b85d060..93254ac5830 100644
--- a/CHANGELOG.unreleased.md
+++ b/CHANGELOG.unreleased.md
@@ -46,6 +46,8 @@ For upgrade instructions, please check the [migration guide](MIGRATIONS.released
 - Fixed a regression which caused that uint16 and uint8 segmentations could not be rendered. [#6406](https://github.com/scalableminds/webknossos/pull/6406)
 - Fixed a bug which prevented keyboard shortcuts from taking affect after expanding/collapsing the sidebar panels using the button icons.[#6410](https://github.com/scalableminds/webknossos/pull/6410) 
 - Fixed a bug with the clip histogram button to prevent it from showing a loading spinner forever in some cases. [#6407](https://github.com/scalableminds/webknossos/pull/6407)
+- Fixed an issue whereby a warning toast would be triggered every time the 3D viewport is put into fullscreen mode. [#6412](https://github.com/scalableminds/webknossos/pull/6412)
+
 
 
 ### Removed
diff --git a/frontend/javascripts/oxalis/model/sagas/dataset_saga.ts b/frontend/javascripts/oxalis/model/sagas/dataset_saga.ts
index 46d321d6013..8c84fcc42f0 100644
--- a/frontend/javascripts/oxalis/model/sagas/dataset_saga.ts
+++ b/frontend/javascripts/oxalis/model/sagas/dataset_saga.ts
@@ -1,11 +1,15 @@
+import { call, take, takeEvery, takeLatest } from "typed-redux-saga";
+import { sum } from "lodash";
 import type { Saga } from "oxalis/model/sagas/effect-generators";
 import { select } from "oxalis/model/sagas/effect-generators";
-import { call, take, takeEvery, takeLatest } from "typed-redux-saga";
+
 import { sleep } from "libs/utils";
-import { getEnabledLayers } from "oxalis/model/accessors/dataset_accessor";
 import Toast from "libs/toast";
 import messages from "messages";
+import { getEnabledLayers } from "../accessors/dataset_accessor";
 import { getCurrentResolution } from "../accessors/flycam_accessor";
+import { getViewportExtents } from "../accessors/view_mode_accessor";
+
 export function* watchMaximumRenderableLayers(): Saga<void> {
   function* warnMaybe(): Saga<void> {
     const maximumLayerCountToRender = yield* select(
@@ -50,9 +54,17 @@ export function* watchZ1Downsampling(): Saga<void> {
     const minVoxelPerPixel = 0.1;
     if (!userClosedWarning) {
       // checking only the downsampled dimensions x and y
+      const extents = yield* select((state) => getViewportExtents(state));
+      const areas = [extents.PLANE_XY, extents.PLANE_YZ, extents.PLANE_XZ].map(
+        ([width, height]) => width * height,
+      );
+      const areDataviewportsInvisible = sum(areas) === 0;
+
       const showWarning =
-        currentZoomStep / currentRes[0] < minVoxelPerPixel ||
-        currentZoomStep / currentRes[1] < minVoxelPerPixel;
+        (currentZoomStep / currentRes[0] < minVoxelPerPixel ||
+          currentZoomStep / currentRes[1] < minVoxelPerPixel) &&
+        !areDataviewportsInvisible;
+
       if (showWarning) {
         Toast.warning(messages["dataset.z1_downsampling_hint"], {
           sticky: true,