This looks like a browser issue, though I've never seen this particular symptom.
Here are some questions/things-to-try:
Here are some questions/things-to-try:
- Does the problem occur with other browsers (e.g. Edge, Chrome)?
- Does the problem occur in Chrome if you open an incognito window? If so, you probably have a bad extension installed, or some weird cookie or cache issue. [I assume you've at least closed all your browser windows and rebooted, by the way.]
- If you open the browser developer panel (type SHIFT + CTRL + I) and select the Console tab, do you see any error message when you load the editing page and start editing?
- You say the problem is new. Do you mean you've been using CodeRunner fine up until now? If so, what might have changed (browser or OS upgrades, Moodle upgrade, etc)?
- You say the problem occurs during editing. So is the Ace editor (which is the code editor you're using when editing questions) working OK when you preview questions?
As a temporary emergency work-around, if you type CTRL + ALT + M you will turn off the Ace editor and be presented with a standard HTML Text Area. This should work (inelegantly).
Richard