diff --git a/grader_labextension/grader_labextension/handlers/version_control.py b/grader_labextension/grader_labextension/handlers/version_control.py
index 7c8074ec..85520011 100644
--- a/grader_labextension/grader_labextension/handlers/version_control.py
+++ b/grader_labextension/grader_labextension/handlers/version_control.py
@@ -303,14 +303,8 @@ async def put(self, lecture_id: int, assignment_id: int, repo: str):
             self.log.error(e.response)
             raise HTTPError(e.code, reason=e.response.reason)
         
-        # TODO: similar logic for push instruction submission
-        #   however we cannot push to edit repository when no submission exists
-        #   reverse order:
-        #   first create submission (with fake commit hash since autograder does not need any commit hash if submission is set to edited),
-        #   then set submission to edited and update username to student username -> need to be able to set this later (in PUT?) -> also refactor SubmissionEditHandler? -> create new endpoint?
-        #   then push to edit repository directly (not using SubmissionEditHandler),
-        
-        # differentiate between "normal" edit and "create" edit by sub_id -> if it is None we know we are in submission creation mode instead of edit mode
+        # differentiate between "normal" edit and "create" edit by sub_id -> if it is None we know we are in
+        # submission creation mode instead of edit mode
         if repo == "edit" and sub_id is None:
             submission = Submission(commit_hash="0" * 40)
             response: dict = await self.request_service.request(
@@ -443,6 +437,7 @@ async def put(self, lecture_id: int, assignment_id: int, repo: str):
             git_service.push(f"grader_{repo}", force=True)
         except GitError as e:
             self.log.error("GitError:\n" + e.error)
+            git_service.undo_commit()
             raise HTTPError(HTTPStatus.INTERNAL_SERVER_ERROR, reason=str(e.error))
 
         if submit and repo == "assignment":
diff --git a/grader_labextension/grader_labextension/services/git.py b/grader_labextension/grader_labextension/services/git.py
index e00d18a2..c0b64751 100644
--- a/grader_labextension/grader_labextension/services/git.py
+++ b/grader_labextension/grader_labextension/services/git.py
@@ -140,6 +140,12 @@ def go_to_commit(self, commit_hash):
         self.log.info(f"Show commit with hash {commit_hash}")
         self._run_command(f"git checkout {commit_hash}", cwd=self.path)
 
+    def undo_commit(self, n: int = 1) -> None:
+        self.log.info(f"Undoing {n} commit(s)")
+        self._run_command(f"git reset --hard HEAD~{n}", cwd=self.path)
+        self._run_command(f"git gc", cwd=self.path)
+
+
     def pull(self, origin: str, branch="main", force=False):
         """Pulls a repository
 
diff --git a/grader_labextension/src/components/coursemanage/assignment.tsx b/grader_labextension/src/components/coursemanage/assignment.tsx
deleted file mode 100644
index 4087d3df..00000000
--- a/grader_labextension/src/components/coursemanage/assignment.tsx
+++ /dev/null
@@ -1,189 +0,0 @@
-// Copyright (c) 2022, TU Wien
-// All rights reserved.
-//
-// This source code is licensed under the BSD-style license found in the
-// LICENSE file in the root directory of this source tree.
-
-import * as React from 'react';
-import {
-  Box,
-  Card,
-  CardActionArea,
-  CardContent,
-  Divider,
-  Typography
-} from '@mui/material';
-
-import { Assignment } from '../../model/assignment';
-import { Lecture } from '../../model/lecture';
-import {
-  getAllSubmissions,
-  getProperties
-} from '../../services/submissions.service';
-import {
-  getAssignment,
-  getAssignmentProperties
-} from '../../services/assignments.service';
-import { AssignmentModalComponent } from './assignment-modal';
-import { DeadlineComponent } from '../util/deadline';
-import { blue } from '@mui/material/colors';
-import { getFiles, lectureBasePath } from '../../services/file.service';
-import { openBrowser } from './overview/util';
-import { CardDescriptor } from '../util/card-descriptor';
-import { enqueueSnackbar } from 'notistack';
-import {
-  deleteKey,
-  loadNumber,
-  storeNumber
-} from '../../services/storage.service';
-import { Link } from 'react-router-dom';
-
-/**
- * Props for AssignmentComponent.
- */
-export interface IAssignmentComponentProps {
-  lecture: Lecture;
-  assignment: Assignment;
-  root: HTMLElement;
-  users: any;
-  onDeleted: () => void;
-}
-
-/**
- * Renders an assignment card which opens onclick the assignment modal.
- * @param props Props of assignment functional component
- * @constructor
- */
-export const AssignmentComponent = (props: IAssignmentComponentProps) => {
-  const [assignment, setAssignment] = React.useState(props.assignment);
-  const [displaySubmissions, setDisplaySubmissions] = React.useState(
-    loadNumber('cm-opened-assignment') === props.assignment.id || false
-  );
-  const [files, setFiles] = React.useState([]);
-  const onSubmissionClose = async () => {
-    setDisplaySubmissions(false);
-    deleteKey('cm-opened-assignment');
-    setAssignment(await getAssignment(props.lecture.id, assignment.id));
-    props.onDeleted();
-  };
-
-  const [allSubmissions, setAllSubmissions] = React.useState([]);
-  const [latestSubmissions, setLatestSubmissions] = React.useState([]);
-  const [numAutoGraded, setNumAutoGraded] = React.useState(0);
-  const [numManualGraded, setNumManualGraded] = React.useState(0);
-  React.useEffect(() => {
-    getAllSubmissions(props.lecture.id, assignment.id, 'none', true).then(
-      response => {
-        setAllSubmissions(response);
-        let auto = 0;
-        const autoUserSet = new Set<string>();
-        let manual = 0;
-        const manualUserSet = new Set<string>();
-        for (const submission of response) {
-          if (
-            submission.auto_status === 'automatically_graded' &&
-            !autoUserSet.has(submission.username)
-          ) {
-            autoUserSet.add(submission.username);
-            auto++;
-          }
-          if (
-            submission.manual_status === 'manually_graded' &&
-            !manualUserSet.has(submission.username)
-          ) {
-            manualUserSet.add(submission.username);
-            manual++;
-          }
-        }
-        setNumAutoGraded(auto);
-        setNumManualGraded(manual);
-      },
-      (error: Error) => {
-        enqueueSnackbar(error.message, {
-          variant: 'error'
-        });
-      }
-    );
-
-    getAllSubmissions(props.lecture.id, assignment.id, 'latest', true).then(
-      response => {
-        setLatestSubmissions(response);
-      }
-    );
-
-    getFiles(`${lectureBasePath}${props.lecture.code}/source/${assignment.id}`).then(files => {
-      setFiles(files);
-    });
-  }, [assignment]);
-
-  return (
-    <Box sx={{ height: '100%' }}>
-      <Card
-        sx={{ maxWidth: 225, minWidth: 225, height: '100%', m: 1.5 }}
-        onClick={async () => {
-          await openBrowser(`${lectureBasePath}${props.lecture.code}/source/${assignment.id}`);
-          setDisplaySubmissions(true);
-          storeNumber('cm-opened-assignment', assignment.id);
-        }}
-      >
-        <CardActionArea
-          sx={{ height: '100%', display: 'flex', flexDirection: 'column' }}
-          component={Link as any}
-          to={`/lecture/${props.lecture.id}/assignment/${props.assignment.id}/`}
-        >
-          <CardContent sx={{ flexGrow: 1 }}>
-            <Typography variant='h5' component='div'>
-              {assignment.name}
-            </Typography>
-            <Typography
-              sx={{ fontSize: 14 }}
-              color='text.secondary'
-              gutterBottom
-            >
-              {files.length + ' File' + (files.length === 1 ? '' : 's')}
-              <Typography
-                sx={{
-                  fontSize: 12,
-                  display: 'inline-block',
-                  color: blue[500],
-                  float: 'right'
-                }}
-              >
-                {assignment.status}
-              </Typography>
-            </Typography>
-            <Divider sx={{ mt: 1, mb: 1 }} />
-
-            <CardDescriptor
-              descriptor={'Point'}
-              value={assignment.points}
-              fontSizeDescriptor={13}
-            />
-            <CardDescriptor
-              descriptor={'User with Submission'}
-              value={latestSubmissions.length}
-              fontSizeDescriptor={13}
-            />
-            <CardDescriptor
-              descriptor={'Autograded Submission'}
-              value={numAutoGraded}
-              ofTotal={latestSubmissions.length}
-              fontSizeDescriptor={13}
-            />
-            <CardDescriptor
-              descriptor={'Manualgraded Submission'}
-              value={numManualGraded}
-              ofTotal={latestSubmissions.length}
-              fontSizeDescriptor={13}
-            />
-          </CardContent>
-          <DeadlineComponent
-            due_date={assignment.due_date}
-            compact={false}
-            component={'card'}
-          />
-        </CardActionArea>
-      </Card>
-    </Box>
-  );
-};
diff --git a/grader_labextension/src/components/coursemanage/lecture.tsx b/grader_labextension/src/components/coursemanage/lecture.tsx
index 618e00ba..2b25fa9b 100644
--- a/grader_labextension/src/components/coursemanage/lecture.tsx
+++ b/grader_labextension/src/components/coursemanage/lecture.tsx
@@ -13,7 +13,7 @@ import {
   Grid,
   LinearProgress, Stack, TableCell, TableRow,
   Typography,
-  Box
+  Box, Tooltip
 } from '@mui/material';
 import * as React from 'react';
 import { Assignment } from '../../model/assignment';
@@ -22,14 +22,13 @@ import {
   createAssignment, deleteAssignment,
   getAllAssignments
 } from '../../services/assignments.service';
-import { AssignmentComponent } from './assignment';
 import { CreateDialog, EditLectureDialog } from '../util/dialog';
 import {
   getLecture,
   getUsers,
   updateLecture
 } from '../../services/lectures.service';
-import { red } from '@mui/material/colors';
+import { red, grey } from '@mui/material/colors';
 import { enqueueSnackbar } from 'notistack';
 import {
   deleteKey,
@@ -88,41 +87,49 @@ const AssignmentTable = (props: IAssignmentTableProps) => {
                 </IconButton>
               </TableCell>
               <TableCell>
-                <IconButton
-                  aria-label='delete assignment'
-                  size={'small'}
-                  onClick={(e) => {
-                    showDialog(
-                      'Delete Assignment',
-                      'Do you wish to delete this assignment?',
-                      async () => {
-                        try {
-                          await deleteAssignment(
-                            props.lecture.id,
-                            row.id
-                          );
-                          enqueueSnackbar('Successfully Deleted Assignment', {
-                            variant: 'success'
+                <Tooltip title={row.status === 'released' || row.status === 'complete'
+                  ? 'Released or Completed Assignments cannot be deleted'
+                  : `Delete Assignment ${row.name}`
+                }>
+                  <span> {/* span because of https://mui.com/material-ui/react-tooltip/#disabled-elements */}
+                    <IconButton
+                      aria-label='delete assignment'
+                      size={'small'}
+                      disabled={row.status === 'released' || row.status === 'complete'}
+                      onClick={(e) => {
+                        showDialog(
+                          'Delete Assignment',
+                          'Do you wish to delete this assignment?',
+                          async () => {
+                            try {
+                              await deleteAssignment(
+                                props.lecture.id,
+                                row.id
+                              );
+                              enqueueSnackbar('Successfully Deleted Assignment', {
+                                variant: 'success'
+                              });
+                              props.setAssignments(props.rows.filter(a => a.id !== row.id));
+                            } catch (error: any) {
+                              enqueueSnackbar(error.message, {
+                                variant: 'error'
+                              });
+                            }
                           });
-                          props.setAssignments(props.rows.filter(a => a.id !== row.id));
-                        } catch (error: any) {
-                          enqueueSnackbar(error.message, {
-                            variant: 'error'
-                          });
-                        }
-                      });
-                    e.stopPropagation();
-                  }}
-                >
-                  <CloseIcon sx={{ color: red[500] }} />
-                </IconButton>
+                        e.stopPropagation();
+                      }}
+                    >
+                    <CloseIcon
+                      sx={{ color: (row.status === 'released' || row.status === 'complete') ? grey[500] : red[500] }} />
+                  </IconButton>
+                  </span>
+                </Tooltip>
               </TableCell>
             </TableRow>
           );
         }}
       />
     </>
-
   );
 };
 
diff --git a/grader_labextension/src/components/coursemanage/settings/settings.tsx b/grader_labextension/src/components/coursemanage/settings/settings.tsx
index 9b6a4972..3361cfa3 100644
--- a/grader_labextension/src/components/coursemanage/settings/settings.tsx
+++ b/grader_labextension/src/components/coursemanage/settings/settings.tsx
@@ -6,7 +6,7 @@ import {
   Box,
   Button,
   Checkbox,
-  FormControlLabel,
+  FormControlLabel, IconButton,
   InputLabel,
   MenuItem,
   Stack,
@@ -25,12 +25,14 @@ import { enqueueSnackbar } from 'notistack';
 import { Lecture } from '../../../model/lecture';
 import * as yup from 'yup';
 import { SectionTitle } from '../../util/section-title';
-import { useRouteLoaderData } from 'react-router-dom';
+import { useNavigate, useRouteLoaderData } from 'react-router-dom';
 import { getLateSubmissionInfo, ILateSubmissionInfo, LateSubmissionForm } from './late-submission-form';
 import { FormikValues } from 'formik/dist/types';
 import { SubmissionPeriod } from '../../../model/submissionPeriod';
 import moment from 'moment';
 import { red } from '@mui/material/colors';
+import { showDialog } from '../../util/dialog-provider';
+import CloseIcon from '@mui/icons-material/Close';
 
 const gradingBehaviourHelp = `Specifies the behaviour when a students submits an assignment.\n
 No Automatic Grading: No action is taken on submit.\n
@@ -62,6 +64,7 @@ const validationSchema = yup.object({
 //}
 
 export const SettingsComponent = () => {
+  const navigate = useNavigate();
 
   const { lecture, assignments } = useRouteLoaderData('lecture') as {
     lecture: Lecture,
@@ -341,9 +344,52 @@ export const SettingsComponent = () => {
                 <MenuItem value={'group'}>Group</MenuItem>
               </Select>*/}
         </Stack>
-        <Button sx={{ mt: 2 }} color='primary' variant='contained' type='submit'>
-          Save changes
-        </Button>
+        <Stack direction={'row'} spacing={2} sx={{ mt: 2 }}>
+          <Button sx={{ whiteSpace: 'nowrap', minWidth: 'auto' }} color='primary' variant='contained' type='submit'>
+            Save changes
+          </Button>
+          <Box sx={{ flex: '1 1 100%' }}></Box>
+          <Tooltip title={assignment.status === 'released' || assignment.status === 'complete'
+            ? 'Released or Completed Assignments cannot be deleted'
+            : `Delete Assignment ${assignment.name}`
+          }>
+            <span> {/* span because of https://mui.com/material-ui/react-tooltip/#disabled-elements */}
+              <Button
+                sx={{ whiteSpace: 'nowrap', minWidth: 'auto' }}
+                aria-label='delete assignment'
+                size={'small'}
+                color={'error'}
+                variant='contained'
+                disabled={assignment.status === 'released' || assignment.status === 'complete'}
+                onClick={(e) => {
+                  showDialog(
+                    'Delete Assignment',
+                    'Do you wish to delete this assignment?',
+                    async () => {
+                      try {
+                        await deleteAssignment(
+                          lecture.id,
+                          assignment.id
+                        );
+                        enqueueSnackbar('Successfully Deleted Assignment', {
+                          variant: 'success'
+                        });
+                        navigate(`/lecture/${lecture.id}`);
+                      } catch (error: any) {
+                        enqueueSnackbar(error.message, {
+                          variant: 'error'
+                        });
+                      }
+                    });
+                  e.stopPropagation();
+                }}
+              >
+                Delete Assignment
+              </Button>
+            </span>
+          </Tooltip>
+        </Stack>
+
       </form>
     </Box>
   );
diff --git a/grader_labextension/src/widgets/assignmentmanage.tsx b/grader_labextension/src/widgets/assignmentmanage.tsx
index 4b75ab7f..d8475110 100644
--- a/grader_labextension/src/widgets/assignmentmanage.tsx
+++ b/grader_labextension/src/widgets/assignmentmanage.tsx
@@ -26,7 +26,7 @@ export class AssignmentManageView extends ReactWidget {
 
   constructor(options: AssignmentManageView.IOptions = {}) {
     super();
-    this.id = options.id;
+    this.id = options.id || "assignment-view";
     this.addClass('GradingWidget');
 
     const savedPath = loadString('assignment-manage-react-router-path');
@@ -50,6 +50,8 @@ export class AssignmentManageView extends ReactWidget {
       <ThemeProvider theme={createTheme({ palette: { mode: this.theme } })}>
         <CssBaseline />
         <SnackbarProvider maxSnack={3}
+                          // the parent of the parent is the main dock panel in JupyterLab
+                          domRoot={this.node.parentNode.parentElement}
                           action={(snackbarId) => (
                             <Button variant='outlined' size='small' style={{ color: 'white', borderColor: 'white' }}
                                     onClick={() => closeSnackbar(snackbarId)}>
diff --git a/grader_labextension/src/widgets/coursemanage.tsx b/grader_labextension/src/widgets/coursemanage.tsx
index fc07e4a6..c01166bc 100644
--- a/grader_labextension/src/widgets/coursemanage.tsx
+++ b/grader_labextension/src/widgets/coursemanage.tsx
@@ -26,7 +26,7 @@ export class CourseManageView extends ReactWidget {
 
   constructor(options: CourseManageView.IOptions = {}) {
     super();
-    this.id = options.id;
+    this.id = options.id || "course-manage-view";
     this.addClass('GradingWidget');
 
     const savedPath = loadString('course-manage-react-router-path');
@@ -50,6 +50,8 @@ export class CourseManageView extends ReactWidget {
       <ThemeProvider theme={createTheme({ palette: { mode: this.theme } })}>
         <CssBaseline />
         <SnackbarProvider maxSnack={3}
+                          // the parent of the parent is the main dock panel in JupyterLab
+                          domRoot={this.node.parentNode.parentElement}
                           action={(snackbarId) => (
                             <Button variant='outlined' size='small' style={{ color: 'white', borderColor: 'white' }}
                                     onClick={() => closeSnackbar(snackbarId)}>