According to the javaFX API doc,

Stage {
.........................
resizable : false
..........................
.........................
}

sould not allow to change the size of the stage. What if, we try to change the size of the stage programmatically (by binding values) ?

Here I am attaching a Netbeans project where I am setting the resizable attribute to false and then trying to change the size of the Stage by binding the value of a slider with the height and width of the Stage.

It allows to change the size of the Stage ! If by any chance, this is the expected behaviour, it should be documented well.