A few times this calendar year, the menus in a newly-opened Developer Console are not responsive to mouse clicks. Nothing happens.

The IDE workspace has become corrupted. Here is how you can quickly resolve it:

1. Go to Salesforce Workbench
2. Go to the REST Explorer and enter this GET query: /services/data/v36.0/tooling/query/?q=select+id,lastModifiedBy.name,+lastmodifiedDate+from+IDEWorkspace+where+lastmodifiedBy.name='your name'+order+by+lastmodifiedDate+desc+limit+1
3. Copy to the clipboard the value of the ID field in the Raw Response result
4. Do a REST Delete that looks like: /services/data/v36.0/tooling/sobjects/IDEWorkspace/theIdeWorkspaceId


Close and reopen the Developer Console and you should be good to go.