Cannot edit landscape splines location

I’m using UE4 4.25.4 to create a landscape with splines, but I got an issue.
The spline creation is ok, but when I click on “Select all connected: Segments” I lose the ability to change the location of each control point.
If I click on a control point in the viewport, the 3 arrows (red, green, blue) do not show up. The only way to retake control is to restart the project, but it is not the best way to edit splines.
I don’t know if I’m missing a shortcut or some steps to do this, or if this is just a bug.
Does somebody else got this problem before?