How to have success using PROP:Mark on a List?

I have now spent too much time attempting to use PROP:Mark on an ABC Browse List in order to implement a very simplified class for standard Windows CtrlMouseLeft record marking. If anyone has had success in doing this AND would like to share the secret, I’d certainly be interested.

The primary problem is how to get multiple marked records to display highlighted. My understanding was that PROP:Mark would handle this.

BTW - I do have SuperTagging and have yet to get it to work as desired in my App.

PROP:Mark is not the tree you want to bark up, especially if you have a lot of records or a page loaded browse. It does not provide the functionality that you’d expect.

Attached, is some stuff I wrote over 20 years ago, and it kind of makes me cringe to look at stuff I wrote that long (777.7 KB)
. But if it helps you come up with a solution, give it a look.

I think there are other PROP:VLB contributions in the community.

Thank you, Jeff. I am sure I can get an adaption of your code to work.

At this point, the only problem I have with using PROP:Mark in my class is getting the highlight to display. I can force this by specifying highlight colors for every column (several). However, I still have some suspicions that PROP:Mark has some minor, undocumented detail. I say this is because MH does not use VLB in the SuperTagging browse marking template AND I trust that it normally works as advertised.

Time spent sorting out what should be a basic BrowseClass feature reminds me of all the low hanging potential SV has left incomplete and ignored over the years.

Thanks again and though perhaps dated, your code example was easily understood.