You've hit the nail on the head, in my opinion, PiepMGI! BI were informed that the onDrag EH (CT_ListNBox) was broken in the development branch three weeks before the public release of 1.48 and failed to fix it. It is arguably the most important EH for that CT, I know of several missions and modifications that rely on it. Modifications were obviously made to the CT because there are references to them in the changelog, but instead of asking the developer who made the changes to take a quick look and see what could have broken it they decided to simply release the patch with the bug and throw the developers that rely on it into the wind. The development branch is there to avoid these exact issues from occurring. You cannot simply break, to the point of complete failure, previously working commands/features in the development branch and then ignore the reports (or assign them to developers and forget about them) and release them into the public domain. Community developers spend hundreds of hours of their own time developing missions/modifications for Arma 3 and it is completely unacceptable to ruin their work through pure laziness!
If something that was previously working breaks in the development branch then obviously a modification has caused this and it should be fixed BEFORE the public release. Contact the developer that was working on any related issues and ask them to take a look! It's common sense and basic professionalism!