When debugging an agent, the first click to select and agent fails.

Steps to reproduce:

1. Click on the debug button.

2. Select an agent.

3. See that the graph debugging is not updating until you click a second time.

Actual results: The debug view is not updated correctly & the agent is not selected.

Expected results: The agent should be selected correctly on first click & debugging should be visible.

Reproducible with versions: Unity 6.000.0.23f1

Tested on (OS): Mac