Is it not possible to extend classes like SButton or SBorder?

Hello,

I need to modify some function inside an SButton and SBorder to create custom functionality, however, when I click on New C++ class, all the classes beginning with “S” don’t pop up and I can’t seem to be able to extend any of those classes manually either. Can anyone tell me if those classes are extendable in any way?

Thanks in advance.

You can, you just need to add the code manually. The only classes the editor knows about are the reflected ones.

In order to do it manually, the class needs to be declared in a header in a module’s Public folder, and have the MODULENAME_API prefix in front of its name at declaration. Pretty sure that is the case for the majority of the standard Slate controls such as those you mention.