Selecting an object on a different floor can lock the camera focus

Description:
Selecting an object and then selecting another object located on a different floor can cause the camera to enter an invalid state.

After this happens, every time an object is selected, the camera focus is reset to the maximum distance. This makes camera navigation difficult or impossible, as panning and zooming are constantly interrupted.

Steps to reproduce:

1. Select an object on one floor

2. Select an object located on a different floor

3. Continue selecting different objects

4. Try to move the camera with middle click or scroll

Actual behavior:
The camera focus resets to the maximum distance every time an object is selected, preventing normal camera movement and zoom.

Expected behavior:
Selecting objects on different floors should not affect the camera state. The camera focus should remain stable and camera controls should continue to work normally.