### Steps to reproduce

1. Have two project phases with gates

2. Make sure the gates are close to each other

3. Go to the overview of a project with those gates

4. In the timeline widget zoom out, so that the two gates cluster to one

5. Hover over the cluster


### What is the buggy behavior?

* The tooltip shows "invalid date" and the icon and label for a phase


### What is the expected behavior?

* The tooltip should show the correct dates

* It should show the icon and label for gates Begin of the insertionin greyEnd of the insertion

* Begin of the insertionItEnd of the insertion Begin of the deletion If possible, itEnd of the deletion should show the Begin of the insertionnamesEnd of the insertion Begin of the deletion numberEnd of the deletion of clusterd gates


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