Right you are!
Stu, do you remember when Joz Baz and I reported that the Manual Override fields in the Current Conditions Calculator were greyed out and appeared to be non-editable, but they were in actual fact editable? This is exactly what happened to me when I was entering the WU Camera ID. Whilst I was adding the Camera ID, both the Camera ID field and the Update Rate field greyed out and could not be edited. However, I selected the field anyway, edited it and it appeared to take the change. Later, I discovered that the entire Preferences window was locked up. I eventually restarted WeatherCat when I could not get anything to work in Preferences. When I went back into Preferences after the restart, I was able to add the Camera ID (I think my earlier attempt had a space behind the last character). When I tried to edit the Update Rate, both fields greyed out again. This time, I just unchecked the Upload Webcam Image box and when I rechecked it, I was able to change the Update Rate.
Bottom line, I am now uploading webcam images to Wunderground through WeatherCat, but there are some strange happenings in the Wunderground PWS preferences pane.