Hi, I cant give quick answer. I know what you mean. I tried to fix drag issue many times, but for some games is not possible. I will think about this and will write answer later. Its not easy for quick answer.
I had dragging troubles in fallout too and I implemented one feature to Touch Widget – ignore next mouse up.
I did not used it for a long time and maybe its broken, because I rewrote a lot of code since I used it, but maybe it can help.
Idea is : hold touch widget and click on item to move, then on place where you want drop it.