moving one task from one row to another

[ketanco]

i was reviewing my schedule and i saw an activity on line 20. i wanted to move it to line 27, so i just dragged it but it surprisingly made the activity on line 28 a successor of it, although i jst wanted to move the activity and do nothing else. why did it reassign relationships and how can i prevent it? i did the moving because that activity was going to take place a little later than the ones listed below it so on te bar chart it did not look so neat. so i did it to show it neat but didnt mean to reassign any new relations.