Problem with Global.HEExitPublication and TOC

I trialled HTML Ex. back in 2015 and admit I gave up with it. I decided to try again:

HTML Executable 4.9.4 Windows 10

Adding TOC to publication:

I created a publication with a TOC which all works correctly but when I try to close the book using Global.HEExitPublication I get an Access Violation.

When I select “Contents not visible” on the “Contents Bar” in “Visual Controls” and try to close the publication with Global.HEExitPublication the book remains open and has to be ended using Task Master.

Did you add a custom button to invoke Global.HEExitPublication?

Hi, yes I added a custom buttom.

We added the problem to our TODO list to try to reproduce it.