Your Incident grid (List view for your layout) has its properties set to "Open in New Tab". And if this is set for all roles for all your users and selecting an Incident from the grid opens a new tab which runs the "All" search group, then most definitely this can cause performance issues.
To change this:
1. Select Configure Application.
2. Go to Business Objects>> Incident.
3. Go to the Lists tab and Edit the grid that is used by your layout (to find grid being used, see section named "Identify Grid Used in Layout" below):
5. Change the "Open in New Tab" option to No, shown as Yes below:
6. Save the changes.
7. Refresh the application side and open your Incident grid and double-click an Incident to test.
Identify Grid used in Layout:
1. In Business Objects>> Incident, go to the Layouts tab.
2. Edit the Layout used for your role.
3. Under Views in this Layout section click on "gridView".
4. The grid being used for the Layout will show next to the "List:" label like below: