Bug 1230217

+++ This bug was initially created as a clone of Bug #1230212 +++

Description of problem:
When there are some components (i.e. tasks) in different swimlanes (swimlane1.png), they are overlapped if selected and dragged to the side (swimlane2.png and swimlane3.png). 

For better understanding, there is a process with two lanes, process starts in lane1 and finish in lane2 (swimlane1.png). If I select the last two tasks as in picture swimlane2.png and drag it to the side, the existing task in lane2 will be overlapped (swimlane3.png). It seems like the task is losing the reference with the lane2.

It is very laborious adjust all components/tasks again to the correct lane when it happens in a large process.

Version-Release number of selected component (if applicable):
BPM Suite 6.1.0

How reproducible:
Always

Steps to Reproduce:
1. Create a process with two lanes and some tasks in both (swimlane1.png);
2. Select the last tasks as in picture swimlane2.png;
3. Drag them to the side. The task in the second lane should be overlapped.

Actual results:
swimlane3.png (task is overlapped).

Expected results:
It should not be overlapped by the lane. In a large process is very laborious to put everything in the right place again.

Additional info: