I checked your code and I suggest you to
1- create a global variable named for example : dragged.
2- on dragStop : set its value to true
function dragStop() {
dragged = true;
// Your code here
}
3- In your functions MyFunction_overmij, MyFunction_blog, ... check on this variable (dragged) value.
function MyFunction_overmij() {
if(dragged) {
dragged = false;
return;
}
//your code here
}
//and so on
Note the variable value re-initialization to false so that the next click on any button would work with no issue.
Hope it helps!