Given a tracker with a parent tracker in the hierarchy,
When I open the modal in planning v2 to

• add a child to an element or
• add a submilestone
• add a new item to the backlog

Then the modal will take very long to load because it will wait until all potential parent elements (all parent tracker artifacts) are loaded.

But it's unnecessary as in most cases a parent artifact is already given to the artifact (e.g. the current milestone) and the user cannot select another !

The parent tracker artifacts should only be loaded when creating an artifact and only when the given parent artifact's tracker is not the same as the current tracker's parent. 

For example: when in a Release I'm creating a new User story, whose parents are Epics, then because Release is different than Epics, I should be able to select a parent artifact.

When in a Release I'm creating a new Sprint, whose parent is Release, then I should not be able to select a parent artifact.