paint bucket not working on closed empty spaces

[Fabien]

I use Inkscape 0.92.1 (latest version in the repos) on Ubuntu 17.04 (up to date). When I draw a rectangle, a circle or any closest surface and try to use the paint bucket inside, it just doesn't work. However, when I try to use the paint bucket on an already colored surface (if the rectangle or circle is already filled), it works as usual.