Unable to select text to edit or delete

Recently, I've noticed on my laptop that when I create a new iCloud Calendar event I am unable to select one or more words with either my mouse or CTRL-A to delete or edit. I can't even select the default 'New Event' text to replace it. Instead, I'm forced to place the cursor to the right of Event and repeatedly hit the [Delete] key.

This used to work and now no longer does. I've tried this in both Chrome and Edge. No joy.