The console shows an error message after about 20seconds

For your information:

Recently I noticed an error message in the console, that always seemed to appear after a while. So, I created an empty Web Core program, consisting of an empty unit doing nothing at all. I compiled, ran it and waited for about 20 seconds.... The error message below appeared for this empty program: (1.5 MB)

The error currently doesn't seem to harm the proper operation of an application, but I wonder if this may becoming a blocking error in the future. A search on Internet indicated that this error may be caused by browser extensions. So, I disabled the extensions one by one to find out that it was the Acrobat pdf reader extension.

It is annoying to get error messages that are unrelated with an actual development. I just wanted to report it, as this may bother other developers as well.

Browser extensions can indeed be the source of errors in the console. I've seen this happening already with multiple extensions here. I would hope that the browser could make the source of this error better visible in the browser console so it leads less to confusion.