Steps to reproduce:

1. Create map with 2 elements of type 'trigger', each linked with different trigger. Save it;
2. Enter edit mode;
3. Change the first element's type to 'host' and press apply to confirm changes;
4. Now, click on the second element to open its properties window.

Result:
Second element now have 2 triggers linked to it - one from the first element as well as the original one. Pressing 'apply' user can even save that.

Expected:
Trigger from the first element should be forgotten since it's map element now has changed the type.