### **Environment**:

Your OpenProject Version: 10.2.1

Operating System / Browser / Language: GNU/Arch Linux / Mozilla Firefox 70.0.1 (64-bit) / English

### **Logs**

```text
GEThttps://community.openproject.com/assets/frontend/0.ca1cff9e2823bb96e74a.js
[HTTP/2.0 200 OK 478ms]

GEThttps://community.openproject.com/assets/frontend/7.34308f20346fba52d68f.js
[HTTP/2.0 200 OK 164ms]

GEThttps://community.openproject.com/assets/frontend/common.3a10411beb65f00e02af.js
[HTTP/2.0 200 OK 242ms]

GEThttps://community.openproject.com/assets/frontend/50.3c4e26dc9f924d681dcc.js
[HTTP/2.0 200 OK 167ms]

XHRPOSThttps://sentry.openproject.com/api/11/store/?sentry_key=e89843ed5d464a75ac3440e133458b38&sentry_version=7
[HTTP/2.0 200 OK 400ms]

ERROR An internal error has occurred. breadcrumbs.js:64:49
_instrumentConsole breadcrumbs.js:64
Angular 2
handleError hal-aware-error-handler.ts:32
Angular 2
RxJS 5
Angular 2
invoke polyfills.b4c5289cfe5242e4f192.js:1
run polyfills.b4c5289cfe5242e4f192.js:1
Angular 2
handleError polyfills.b4c5289cfe5242e4f192.js:1
runTask polyfills.b4c5289cfe5242e4f192.js:1
invokeTask polyfills.b4c5289cfe5242e4f192.js:1
_ polyfills.b4c5289cfe5242e4f192.js:1
m polyfills.b4c5289cfe5242e4f192.js:1
XHRPOSThttps://sentry.openproject.com/api/11/store/?sentry_key=e89843ed5d464a75ac3440e133458b38&sentry_version=7
[HTTP/2.0 200 OK 332ms]

```

### **Steps to reproduce:** Begin of the insertion

End of the insertion Begin of the deletion





End of the deletion 1. Go to work package creation form
2. Click on _Switch to Markdown source_ button in the _Description_ editor toolbar.
3. Enter `~~~ test ~~~` as the description
4. Click on _Switch to WYSIWYG editor_ button in the _Description_ editor toolbar.
5.


### **Actual Behavior**

_Description_ Markdown is rendered, _Description_ editor is usable.

### **Expected Behavior**

Markdown is not rendered, the editor becomes unusable.