Construction mode bug - Sims 2 Legacy

Hello, I have a problem in the construction mode. I can't change the floor on some places in the house, especially on the upper floor.

How can I fix this ?

Here is a screenshot : You can't see my pointer on the screenshot but it was next to the "0 § 1x1" in the white rectangle. For example here I can't change the floor on the white rectangle and the furnitures in buy mode don't show the grid at this place.

Thanks for your answers !