I have spent some time investigating options within Lubuntu, without finding any references to ALT key options.
Separately, on Lubuntu Discourse, a contributor got me looking at OpenBox and the configuration file ' rc.xml '.
This could be central to the problem, but my editing of it has only produced error messages.
I have to learn how to successively edit/run configuration files.
This thread was in the hope others had already been down the path and had a packaged solution.
Interestingly, my workshop computer runs Ubuntu Mate, but without CamBam due to poor internet reception.
I will transfer it to house, install CamBam, and examine the options available.
If I can solve the 3D scrolling problem, I will purchase the latest CamBam.
Keep well, John.