Debug error message shows then instantly disappears

[Roy Brophy]

Using Windows 10 desktop, Google Sheets scripting, Chrome

I have a bug. When I run in debug mode it bumps into the bug and stops. It shows the details in the panels at the bottom of the window just fine. However the red error message at the top of the window flashes up and then disappears.

I have searched but found nothing.

I have also turned off all Chrome extensions - but that did not help.

See a little screen video here...

https://drive.google.com/open?id=1-hb-O6LnlZOZHHMOQWL4UNO1uwlKMESo

Any help would be appreciated.

Thank Roy.

[Alan Wells]

I would look at the execution transcript for the error message.  Click the View menu, then choose Execution transcript.  

[Roy Brophy]

Of course - many thanks for reminding me. 

That's the problem with being an occasional scripter:-)

I still wonder why the message disappears - I don't think it used to do that.

Many thanks.