Axes, meshes disappear in MPR mode in certain view.

[Hakim-F]

In MPR mode, if you choose the slicing mode in mouse interaction, and you click in the border of a pixel, the axes or/and meshes ... will disappear in another view. However, if you click in the middle of pixel they are visibile.

Even though you slice through the image, the axes and/or meshes ... will still not be visible until you click in the middle of the pixel.

It is pretty hard to explain but here are some images to illustrate the bug :

[mathildemerle]

@Florent2305 the MPR mode does not exist anymore in medInria. This issue could be closed i think

edit: the PR is about 4-views, we can keep the issue